explain xkcd - User contributions [en]

2896: Crossword Constructors

2024-02-21T08:44:41Z

172.68.110.141: AEN is the exception

{{comic
| number = 2896
| date = February 19, 2024
| title = Crossword Constructors
| image = crossword_constructors_2x.png
| imagesize = 285x388px
| noexpand = true
| titletext = Also, we would really appreciate it if you could prominently refer to it as an 'eHit'.
}}

==Explanation==
{{incomplete|Created by a THREE-LETTER WORD THAT STARTS WITH B - Add meanings of words given, if any. Also check whether any of these words are albums or songs already. Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is inspired by a common situation when people try to make {{w|Crossword#American-style crosswords|US-style quick crossword}} puzzles (where the grid is [[media:CrosswordUSA.svg|almost completely filled]] with words). Here, [[Cueball]], [[Hairbun]], and [[White Hat]] are {{w|crossword puzzle}} constructors, but some of the words they would like to use would result in awkward sequences of letters which are not English words or familiar names, such as "aete", "eni", etc. However, they have an idea to write a letter to persuade prominent singers ({{w|Taylor Swift}}, {{w|Ed Sheeran}}, {{w|Nicki Minaj}}, {{w|Ariana Grande}} and {{w|The Weeknd}}) to choose these awkward sequences of letters as titles of their future albums, thereby letting Cueball, Hairbun, and White Hat write clues about those albums and use those letter sequences as answers.

The particular sequences of letters that are selected are notable for their exclusive usage of the {{w|Letter frequency|most common English letters}}. Most of them also begin and end with a vowel. These are two features that are common in "crosswordese", i.e., words which appear significantly more often in crosswords than in reality. Examples of crosswordese that are actually used include the words "{{w|OREO}}", "{{w|Épée|EPEE}}", and "{{w|Yoko Ono|ONO}}".

The title text lists another sequence of awkward letters, "eHit". Here, Cueball, Hairbun, and White Hat ask these singers to refer their hits (popular songs) as "eHit"s, adding the "e" for electronic such as in e-mail and e-dating. This is also a reference to common crossword entries like "E-TAIL" or "E-MAG" which are often criticized for using the prefix "E" to create words that no one really uses.

===Possible unintended meanings of words===
*aete: {{w|Apple_event#Object_Model|AppleEvent Terminology Extension}}
*eni: {{w|Eni|Eni S.p.A.}}, Italian multinational energy company; the name of an {{W|Eniola_Aluko|England footballer}}
*oreta: ''{{w|Oreta}}'', moth genus in family {{w|Drepanidae}}
*aroe: {{w|Aroe}} may refer to: The Aru Islands Regency, islands in eastern Indonesia; Aroe, an alternative name for Aroi, Patras, in western Greece
*oine: {{w|Kusumoto Ine}}, also known as O-Ine, Japanese physician
*aen: {{w|AEN}} may refer to: Acute esophageal necrosis, a rare esophageal disorder; and more
*aerae: ''[[wikt:aerae|aerae]]'' (Latin noun) genitive/dative singular and nominative plural of ''[[wikt:aera#Latin|aera]]'' (era)

''{{w|Enta da Stage}}'' is the debut album by American East Coast hip hop group Black Moon. 
''öine'' means nocturnal/nightly in Estonian, and features in the titles of a number of albums by artists from that country.

The above words and definitions would be considered too obscure for use in most American crossword puzzles, as puzzle editors normally prefer answers to be at least somewhat familiar to the general public, even if the answers wind up being clued obscurely.

===Uses in mainstream crossword puzzles===
Some of these words have appeared in the New York Times crossword, albeit only in the pre-1992 era (that is, before the current editor Will Shortz began his tenure).
*aroe: Clued as an variant spelling for the {{w|Aru Islands Regency}}, and also as part of the phrase "and be thou like unto a roe" from the King James Bible.
*aen: Clued as an abbreviation for the ''{{w|Aeneid}}'' or as an abbreviation for the Latin word ''aeneus'' meaning "of bronze" or "of copper"

==Transcript==
:[Cueball is sitting in an office chair at a table and typing on his laptop, with small movement lines above his hands indicating typing. White Hat and Hairbun are standing behind him and looking at what he writes. The text he writes can be seen above them. The list of words at the end are written in two columns with four words in each. Here below, the second column of words is written below the first:]
:Dear Ms. Swift, Mr. Sheeran, Ms. Minaj, Ms. Grande, and Mr. Weeknd,
:We are a group of crossword puzzle constructors, and we would like to suggest some titles for your future albums:
:*Aete
:*Eni
:*Oreta
:*Aroe
:*Oine
:*Aen
:*Enta
:*Aerae

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Cueball]]
[[Category:Language]]
[[Category:Music]]
[[Category:Comics featuring real people]]

Talk:96: Mail

2022-05-12T12:12:38Z

172.68.110.141: forgot signature

How about a bobcat?[[Special:Contributions/108.162.219.202|108.162.219.202]] 05:57, 30 December 2013 (UTC)

No, but live scorpions are: http://pe.usps.com/text/pub52/pub52c5_007.htm --[[Special:Contributions/173.245.52.205|173.245.52.205]] 15:36, 20 January 2014 (UTC)

I think it's black hat guy on the other end of the phone line. [[Special:Contributions/108.162.221.45|108.162.221.45]] 20:47, 20 January 2014 (UTC)

: If it were the black hat guy, he'd have something more snarky to say. This cueball's character is more in line with beret guy. [[Special:Contributions/108.162.216.39|108.162.216.39]] 07:08, 26 February 2015 (UTC)BK201

:: Black hat does have an obsession about these things. see 325. This seems to be likely that it's him. But ill leave the desicion to someone else. [[Special:Contributions/162.158.2.139|162.158.2.139]] 05:23, 7 June 2016 (UTC)

Did anyone else read it as him not being allowed to mail himself via USPS? --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 17:12, 27 November 2014 (UTC)

A package of time, if it even made sense, would not require time not to be continuous. However I won't remove that paragraph from the explanation. [[Special:Contributions/172.68.26.41|172.68.26.41]] 19:18, 5 September 2017 (UTC)

The second paragraph here is rather unclear and could use some rewriting. Unfortunately, I can't get a good enough grasp of what it's trying to say to do it.
* The first sentence I think is trying to say something like "...time is not continuous - similar to particles in quantum mechanics", but I don't know enough about the subject to know if this makes sense.
* The first part of the second sentence looks like it's trying to say "This is not a widely accepted theory..."
* I don't know what the second part of the second sentence is getting at at all
Can anyone else have a go at it?[[Special:Contributions/141.101.76.16|141.101.76.16]] 12:09, 17 January 2018 (UTC)

isn't pi either close to a number with a fixed number of decimals (as before the revision by M), or equal to a number with indefinite decimals (as indicated by the "...")? So that the combination of close to and the "..." makes it at least inaccurate? As I am not 100% familiar with English mathematical writing: Can someone please verify or contradict my statement? --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 15:00, 12 March 2019 (UTC)
:You can define a rational number that is arbitrarily close to pi (example: off by no more than 1 in 10 to the tenth power). You can never write down (or digitally store) the '''exact''' value of pi. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 03:22, 16 August 2021 (UTC)

It could also be a literal no fly list, as in the insect fly. [[Special:Contributions/172.68.110.141|172.68.110.141]] 12:12, 12 May 2022 (UTC)

Talk:96: Mail

2022-05-12T12:11:54Z

172.68.110.141: flies fly.

2612: Lightsabers

2022-05-04T20:31:03Z

172.68.110.141: Undo revision 243166 by Ex Kay Cee Dee (talk)

<noinclude>''For the comic named "Lightsaber", see [[1433: Lightsaber]].''</noinclude>
{{comic
| number = 2612
| date = April 27, 2022
| title = Lightsabers
| image = lightsabers.png
| titletext = A lot of Jedi romances start with this turning into a Lady and the Tramp spaghetti situation.
}}

==Explanation==
{{incomplete|Created by a MAGNETICALLY CONFINED PLASMA-SABER REACTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
A {{w|lightsaber}} is a fictional beam-like sword weapon used by members of the {{w|Jedi}} order and the {{w|Sith}} in the ''{{w|Star Wars}}'' franchise. This comic shows a lightsaber fight starting between two [[Cueball]]-like Jedi, one already presenting their blade in challenge and the second activating theirs in response. When the first strike is made between the two lightsabers, they meld together with a bloop sound, like the beams are made of a liquid. The two light beams then remain stuck to each other. In in-universe "technical documents", lightsabers are said to be made from magnetically-confined plasma, so perhaps the magnetic fields which were projected from each hilt have merged instead of repelling (or presenting as mutually impervious) as is usually expected.

(This scene actually looks a lot like what happens between Harry Potter and Voldemort's wands in the end of the fourth book, the {{w|Harry Potter and the Goblet of Fire|''Goblet of Fire''}}. Here two spells hit each other and connect the two wands, the wand holders then unable to release or disconnect the wands.)

First the left Jedi, then the right, shakes the hilt, trying to break the bond. When this does not succeed, the right Jedi then deactivates his lightsaber in an attempt to end the connection. This causes the retraction of the entire double-sized light beam into the handles (as seen in the movies), causing both of the Jedi to be drawn together until their heads bonk, forcefully enough to render them both unconscious. The connected lightsaber handles lie next to them on the ground.

The title text implies that such events are how {{w|Jedi}} romances start, comparing it to the famous "spaghetti scene" from the 1955 Disney animated movie ''{{w|Lady and the Tramp}}'' where the two titular characters unintentionally kiss after sharing a strand of spaghetti. In the Old Republic, Jedi were forbidden from entering into romantic relationships (and discouraged from forming attachments in general), but in the pre-Disney ''Star Wars Legends'' continuity of the {{w|Star Wars in other media|Expanded Universe}}, {{w|Luke Skywalker}} and {{w|Mara Jade}} first met while fighting in the aftermath of the fall of the Empire, and then developed a romantic relationship.

Star Wars is a [[:Category:Star Wars|recurring theme]] on xkcd, and lightsabers have been prominently featured before in, for instance, [[1397: Luke]] and [[1433: Lightsaber]], where the problem with the physics of a light beam as a sword is shown. But in general light does not interact with light as {{w|photons}} are {{w|bosons}} and can thus pass through each other. Interference, yes, but two pure light beams cannot collide and bounce back as when two lightsabers collide. Also as the comic Lightsaber mentioned above shows, there is no compatible real-world way of confining a beam of light, making it stop after about a meter (or anywhere){{Dubious}} - see {{w|Optical cavity}}.

==Transcript==
:[Two Cueball like Jedi are engaging each other in a duel using lightsabers over 12 panels of equal size, with sound effects as the only sound. In the first panel the left Jedi has his lightsaber extended holding it in both hand pointing towards the other, who at this time is just turning his lightsaber on.]
:''Tssssss''
:Click

:[Almost same position of the Jedi, but the right Jedi's lightsaber has now extended, making a sound. He is holding it up near his head in both hands]
:''Tsss''

:[Then they run towards each other and swing their lightsabers towards each other, two small arcs indicating the swing of the lightsabers.]

:[The two beams hit each other and connects at the middle in a big bloop of light, with drops of "light" jumping off both above and below the connected lightsabers. Both Jedi still holds on to their handles with both hands. A loud sound comes out of the connection:]
:''Bloop''

:[The Jedi stands still holding their handles. The beam is now forming a bow between the two handles.]

:[The left Jedi violently shakes his handle causing a wave to travel down the beam towards the right Jedi.]
:Shake shake

:[The right Jedi shakes his handle and well and another wave travels the opposite direction towards the left Jedi.]
:Shake shake

:[Back to the bow of light between them, but the beam is visibly still shaking, but no wave is traveling any longer.]

:[Same setting but the shaking has stopped. The right Jedi turns his lightsaber off on his handle with a sound:]
:Click

:[The beam of light is retracted quickly into the handle of the Jedi turning his lightsaber off. So quickly that the two Jedi, still holding on to their handles are pulled up in the air and towards each other as the sound of the beam turning off is heard. Lines indicate their movement and shadows on the ground beneath them indicate they are in the air.]
:''Zhhhiiiip''

:[When the beam is completely retracted the two handles collide and so do the heads of the two Jedi with a loud sound. They still hold on to their handles with both hands. They still hang in the air with shadows on the ground beneath them.]
:''Bonk''

:[In the final panel the two Jedi lie unconscious on the ground with their heads towards each other and with their arms stretched out towards each other. The connected handles lie between them.]

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Multiple Cueballs]]
[[Category:Star Wars]]
[[Category:Fiction]]

2613: Bad Map Projection: Madagascator

2022-05-04T20:30:18Z

172.68.110.141: Undo revision 243159 by Ex Kay Cee Dee (talk)

{{comic
| number = 2613
| date = April 29, 2022
| title = Bad Map Projection: Madagascator
| image = bad_map_projection_madagascator.png
| titletext = The projection's north pole is in a small lake on the island of Mahé in the Seychelles, which is off the top of the map and larger than the rest of the Earth's land area combined.
}}

==Explanation==
This is the fifth comic in the series of [[:Category:Bad Map Projections|Bad Map Projections]] displaying Bad Map Projection #248: Madagascator. It came about 10 months after the fourth [[2489: Bad Map Projection: The Greenland Special ]] (#299).

This time, [[Randall]] used the classic {{w|Mercator projection}} but instead of placing the North Pole on top and the South Pole on the bottom it is oriented so that the top is the island of {{w|Mahé, Seychelles|Mahé}}. The map projection is technically a {{w|Oblique Mercator projection}}, with an unusual choice of the cylinder's axis. Since the Mercator projection tends to visually distort areas near the top and bottom of the resulting map, this gives some areas, notably Madagascar, very unusual shapes, hence the name the ''Madagascator'' — a portmanteau of "Madagascar" and "Mercator"!

The Mercator projection became the standard projection for world maps during the 1800s, because a straight line (or {{w|rhumb line}}) in a Mercator map represents a constant bearing relative to true north. Historically, when navigation was performed by compass, this was a very valuable feature, since one (adjusting for the differences between true and magnetic north) could plot a constant-bearing course between two locations by simply looking at their relative direction on the map.

However, in the mid-20th century, the Mercator was {{w|Mercator_projection#Criticism|criticized}} because it causes distortion near the north and south poles of the map, giving an inaccurate impression of relative sizes. The most commonly given example of this is the size of Greenland — although on the Mercator it appears to be larger than Africa in area, Africa in reality covers an area 14 times that of Greenland.

Randall turns this example on its head by making Madagascar, rather than Greenland, appear larger in the ''Madagascator'' than in reality. By contrast with Greenland, the world's largest non-continent island, Madagascar is only the fourth-largest island in the world, behind Greenland, New Guinea, and Borneo.

To accomplish this, instead of placing the north pole of the map at the geographic North Pole, Randall places the north pole of the map on the island of Mahé in Seychelles. As Madagascar is relatively close to Mahé (around 650 mi (1050 km) distant), placing the north pole of the Mercator projection at Mahé significantly distorts the size of Madagascar, making it appear comparable in size to Europe on the map.

But this distortion is even more pronounced when it comes to the island of Mahé itself, as Randall notes in the title text.
Although Mahé, the largest island in Seychelles with an area of 60.7 square mi (157.2 square km), is minuscule even compared to Madagascar, the claim in the title text that it appears "larger than the rest of the Earth's land area combined" is an understatement.

No part of Mahé is visible in the comic, but clicking on the actual comic will open a website that displays Mercator projections with a pole in any chosen location, with the location of the one opened set to Mahé. The chosen pole is (infinitely far to) the right of the screen, while its {{w|antipodes|antipode}} is on the left. With this, it is possible to see that the island is indeed larger than the rest of the map's land area combined. A single national park within the island rivals Africa in size, and the narrow dirt road closest to the pole appears thicker than Panama. This also reveals that the location of the map's north pole (the "small lake" mentioned by Randall) is the lake impounded by the Rochon Dam, a popular tourist location in Mahé.

Unlike previous Bad Map Projections, Morocco and Western Sahara are drawn as one unlabelled country.

===Comparison of actual/mapped areas===
{| class="wikitable sortable"
! Landmass
! Status
! data-sort-type="number"|Actual Area<ref name="act">Major contiguous land areas that should exclude all islands, ''especially'' major ones, '''''especially''''' especially those listed separately</ref> (Millions of Km²)
! data-sort-type="number"|Proportion Land Area
! data-sort-type="number"|Proportion Image Area<ref name="pri">Of only these listed areas listed</ref>
! data-sort-type="number"|Distortion<ref name="dis">NB. Difference between percentages, rather than percentage difference</ref>
|-
| Africa<ref name="suez">Edge at Suez Canal</ref> || data-sort-value="C2"|Continent 2nd largest || 29.7 || 19.95% || 35% || +15.1%
|-
| Eurasia<ref name="suez" /> || data-sort-value="C1"|Continent Largest || 53.4 || 35.83% || 30% || -5.83%
|-
| North America<ref name="pan">Edge at Panama Canal</ref> || data-sort-value="C3"|Continent 3rd largest || 19.3 || 12.96% || 15% || +2.04%
|-
| South America<ref name="pan" /> || data-sort-value="C4"|Continent 4th largest || 17.8 || 11.96% || 7.8% || -4.16%
|-
| Antarctica<ref name="ice">Significant ice-sheets may complicate mapped/actual 'land' areas</ref> || data-sort-value="C5"|Continent 5th largest || 14.2 || 9.53% || 5.3% || -4.23%
|-
| Madagascar || data-sort-value="I04"|Island 4th largest || 0.592 || 0.40% || 2.9% || +2.50%
|-
| Australia || data-sort-value="C7"|Continent Smallest || 7.55 || 5.07% || 2.5% || -2.57%
|-
| Greenland<ref name="ice" /> || data-sort-value="I01"|Island Largest || 2.17 || 1.45% || 0.87% || -0.58%
|-
| Borneo || data-sort-value="I03"|Island 3rd largest || 0.749 || 0.50% || 0.37% || -0.13%
|-
| New Guinea || data-sort-value="I02"|Island 2nd largest || 0.786 || 0.53% || 0.32% || -0.21%
|-
| Japan<ref name="hon">Honshu only</ref> || data-sort-value="I07"|Island 7th largest || 0.228 || 0.15% || 0.10% || -0.05%
|-
| Mainland Britain || data-sort-value="I09"|Island 9th largest || 0.209 || 0.14% || 0.10% || -0.04%
|-
| Island of Ireland || data-sort-value="I20"|Island 20th largest || 0.082 || 0.05% || 0.03% || -0.02%
|}

<references/>

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
Bad map projection #248: Madagascator

Mercator projection but with the North Pole in the Indian Ocean so it exaggerates the size of Madagascar instead of Greenland. Various countries and oceans are labeled, and country borders are shown.
{{comic discussion}}

[[Category:Bad Map Projections]]

1775: Things You Learn

2022-05-04T17:44:38Z

172.68.110.141: undone obvious vandalism

{{comic
| number = 1775
| date = December 21, 2016
| title = Things You Learn
| image = things_you_learn.png
| titletext = Guess who has two thumbs and spent the night in an ER after trying to rescue a kitten that ran under his car at a stoplight and climbed up into the engine compartment? And, thanks to antibiotics, will continue having two thumbs? THIS GUY. (P.S. kitten is safe!)
}}

==Explanation==
This graph shows various items of information plotted by two criteria: a horizontal "How Bad Is It If You Don't Know [THING]" axis and a vertical "How Easy It Is To Grow Up Without Learning [THING]" axis. Specifically, the vertical axis measures roughly how likely the average person is to remain ignorant of a particular item. The horizontal axis measures the likelihood and severity of bad consequences arising from such ignorance.

The title text describes an encounter Randall had where a cat climbed into the engine compartment of his car. It probably serves as an explanation for the seemingly out of place point on the graph about how serious cat bites are. The "two thumbs" is a reference to a well known type of jokes among English speakers. One of the most frequent forms is one person interrupting another mid-speech and asking "what has two thumbs and doesn't give a f*ck? THIS GUY!", before pointing to themselves with their thumbs. The idea is that you only direct the attention to your thumbs so that they can point back to you, though mentioning the thumbs was not actually required except as a topic change. Randall plays on an inversion of this joke as he (presumably) was bitten on the thumb might have {{w|Amputation|lost a thumb}} or perhaps not have been able to make it at all without the intervention of the ER people. So here the "who has two thumbs", is not a deceiving distraction out of a boring conversation, and the thumbs are actually the focus of the phrase.

{| class="wikitable sortable"
! Ignorance is Bad !! Ignorance is Easy !! Information !! Comments
|-
| not bad || (very, very) easy || 100 digits of {{w|pi}} || Most people know pi to only a few digits (3.14 or 3.1415). The latter is accurate to almost one part in half a million, which is close enough for almost any practical purpose.
|-
| not bad || (very) easy || Lyrics to "{{w|We Didn't Start the Fire}}" || "We Didn't Start the Fire" is a 1989 hit song by Billy Joel. Its lyrics include brief, rapid-fire allusions to more than 100 headline events between 1949, the year of Joel's birth, and 1989. While the chorus is memorable, the verses of the song are just a list of people, events and random things from popular culture. The average person is somewhat more likely to know the lyrics to Billy Joel's 1989 hit song than 100 digits of pi, but not knowing them doesn't really have any serious consequences. This song was again the pun in the title text of [[1794: Fire]], which was a follow up to comic #4 in [[821: Five-Minute Comics: Part 3]].
|-
| (very) bad || (very) easy || That cat bites are really serious and if bitten you need to wash the bite and call a doctor immediately || Most people assume that a cat bite is just a minor injury. In fact, it carries a fairly high risk of infection, which can be dangerous if not treated (by cleaning the bite to reduce the risk, and having a doctor examine the bite victim and apply additional treatments such as antibiotics if needed). At the same time, cat bites are quite rare, as cats default to their claws rather than their teeth when they need to attack something (not that cat claws are bacteria-free zones either, quite the opposite), so most people simply don't have to deal with many cat bites.
|-
| (very, very) bad || (very) easy || The red flags for an abusive relationship || It is fairly easy for someone to fall into a pattern of accepting abuse (particularly if the abuser is skilled at emotional manipulation) without realizing it, and the consequences can be mentally and physically devastating.
|-
| (very, very) bad || easy || The {{w|Stroke#Signs_and_symptoms|signs of a stroke}} || The symptoms of a {{w|stroke}} are somewhat variable, including facial drooping, arm weakness and slurred speech, depending on what areas of the brain are affected, and can be mistaken for other conditions. Identifying a stroke quickly and seeking treatment can make the difference between life and death, or between full recovery and permanent impairment.
|-
| bad || easy || Cough into your elbow, not your hand || Covering a cough with the inside of your elbow helps prevent spreading airborne germs and is generally recommended by medical organisations. Coughing into your hand deposits them onto your hand, where they are much more likely to be spread to another person (via handshake, food preparation, shared objects, etc)
|-
| not (too) bad || hard || How to ride a bike || Most children, especially in the United States[http://www.peopleforbikes.org/statistics/category/participation-statistics#youth], learn to ride a bike at a fairly young age. While this is a useful skill to know for both entertainment and transportation, it would generally not be terrible to not learn this skill, particularly if other forms of transportation are readily available.
|-
| not bad (at all) || hard || How to escape movie {{w|quicksand}} || Quicksand in movies is a common trope, and while its physics often differ from real quicksand, escaping from it is commonly done using similar methods (e.g., not struggling, which increases the quicksand's viscosity). Knowing how to escape from quicksand is important if you sink into it, which is a situation most people are very unlikely to encounter in real life. It is much more likely for characters in movies and TV shows, especially in the 1960s, to encounter and become mired in quicksand than for a real individual to do so as real quicksand is a rare occurrence in most climates on Earth.
|-
| not bad (at all) || (very) hard || Lyrics to "{{w|The Twelve Days of Christmas (song)|12 Days of Christmas}}" || Hearing the same Christmas songs over and over each year makes it hard not to learn the lyrics over time. However, the consequences of not doing so are minimal; at most, ignorance of popular culture may leave your friends [[1769|a bit surprised and dismayed]]. Note that this only refers to learning the lyrics of the "Twelve Days of Christmas," not learning all the lyrics. Most people do not know many of the combination once one gets substantially past five. It is very hard to avoid learning some of the lyrics (especially One and Five), but easy to not know many of the later random ones (such as Eight or Eleven).
|-
| not bad (at all) || (very, very) hard || {{w|Theme music|TV theme songs}} || Most children in developed countries grow up watching at least some television. Many of these television shows play the same theme song before the show starts, and many of these have catchy lyrics. Therefore, by repetition, most children will learn at least one of these growing up, and often many.
|-
| bad || hard || That you have to empty the dryer lint trap || A {{w|clothes dryer}} resembles a washing machine, using hot air to heat clothes so that the water evaporates more quickly.

The dryer's air exhaust and air filter get gradually covered with {{w|lint (material)|lint}} (a kind of dust composed mainly of fiber) and must be cleaned regularly. Failing to remove the lint can cause the dryer to stop working effectively, introduce lint back onto your clothes, or (in extreme cases) start a fire.
|-
| (very) bad || (very) hard || {{w|Stop, drop and roll}} || This is a technique to extinguish a fire on one's own clothing, and is frequently taught to children for safety. Not knowing it (or forgetting it in a panic when the situation arises) can result in severe burns that could have been avoided by following the recommendation.
|-
| (very) bad || (very) hard || That you have to pay taxes || Most residents of most countries are legally obligated to pay taxes to their government. Penalties for not doing so often include large fines, and possibly prison sentences. Fortunately, it is something that children hear about quite a bit so it is very difficult to grow up without learning that it must be done. In [[1971: Personal Data]], [[White Hat]] somehow didn't know about taxes.
|-
|}

==Rankings==

100% not bad: not bad at all . . . 100%>not-badness≥50%: not bad . . . 50%>not-badness≥0%: not too bad

100% very bad: very, very bad . . . 100%>very badness≥50%: very bad . . . 50%>very badness>0%: bad

100% hard: very, very hard . . . 100%>hardness≥50%: very hard . . . 50%>hardness>0%: hard

100% easy: very, very easy . . . 100%>easiness≥50%: very easy . . . 50%>easiness≥0%: easy

==Transcript==
:[A simple X and Y graph, with the X labeled "how bad it is if you don't know {thing}" and ranging from "not bad" to "very bad", and Y labeled "how easy it is to grow up without learning {thing}" and ranging from "easy" to "hard" from top to bottom.]

:[Points on graph from top to bottom on the left side of the Y-axis:]

:100 digits of pi
:Lyrics to ''We Didn't Start the Fire''
:How to ride a bike
:How to escape movie quicksand
:Lyrics to ''12 Days of Christmas''
:TV theme songs

:[Points on graph from top to bottom on the right side of the Y-axis:]

:That cat bites are really serious and if bitten you should wash the bite and call a doctor immediately
:Red flags for an abusive relationship
:Signs for a stroke
:Cough into your elbow, not your hand
:That you have to empty the dryer lint trap
:Stop, drop, and roll
:That you have to pay taxes

{{comic discussion}}

[[Category:Charts]]
[[Category:Scatter plots]]

896: Marie Curie

2022-05-04T01:31:53Z

172.68.110.141: Undo revision 234101 by X. K. C. D. (talk)

{{comic
| number = 896
| date = May 9, 2011
| title = Marie Curie
| image = marie curie.png
| titletext = Although not permanently.
}}

==Explanation==
The comic begins with [[Ponytail]] stating that her teacher told her that if she worked hard (applied herself) she could be the next {{w|Marie Curie}}. But then a distorted {{w|zombie}} Marie Curie (drawn as zombie [[Hairbun]]) walks in and informs Ponytail that she is not the only influential woman scientist, and would wish people would get over her "as the only important female scientist". She then mentions two other important women in science.

Marie Curie was a pioneering research scientist, most famous for her work with radiation, and in isolating {{w|Radium}}, and {{w|Polonium}}. She died from {{w|aplastic anemia}} contracted from exposure to {{w|radiation}} from the extremely radioactive isotopes of Radium and Polonium that she would carry around in her pockets. She ends up warning Ponytail against exposure to radium, stating that ''it kills you'', although as the title text points out, obviously not permanently as she came back as a zombie.

The conversation between [[Ponytail]] and Zombie Marie Curie refers to the fact that Marie is often singled out as the only significant female scientist. Marie points out that this is a poor version of the truth, for two reasons. Firstly, there have been many other significant female scientists, and secondly, Marie asserts that the most significant events in {{w|theoretical physics}} and {{w|mathematics}} do not arise because of an individuals desire for fame, but from passion for the subject and a great deal of dedication and hard work.

As examples of important women scientists the comic mentions {{w|Lise Meitner}} and {{w|Emmy Noether}}.

Lise Meitner was one of the major contributors in the discovery of nuclear fission for which her male colleague {{w|Otto Hahn}} was awarded a {{w|Nobel Prize}} in 1944. In the process she proved that {{w|Enrico Fermi}} had made some wrong assumptions, but he also got a Nobel prize whereas she only got a {{w|National Press Club (United States)|National Women's Press Club}} award as "Woman of the Year" in 1946. As a somewhat late consolation, the element {{w|Meitnerium}} was named after her in 1997 almost 30 years after her death. (She is later mentioned again in [[1584: Moments of Inspiration]]).

{{w|Noether's Theorem}} is widely considered one of the most beautiful and significant theorems used in physics, and its repercussions are still being widely explored to this day. She had to learn mathematics by taking {{w|Academic audit|auditing classes}} at {{w|University of Erlangen}} since she was [https://www.agnesscott.edu/lriddle/women/noether.htm refused the opportunity to take classes because she was a woman]. And later she had to teach without getting paid and under male colleagues' names, meaning that students would only take the course if they thought some "real" male teacher was guiding Emmy. Much later Emmy was referenced in the title text of [[2595: Advanced Techniques]].

Marie asserts at the end that Ponytail is not alone, meaning that there are many important female scientists out there, and also many young woman wanting to become scientists. But could also be a reference to the fact that, as mentioned, female scientists might be less likely to receive medals or other tokens of support and encouragement.

Zombies are a [[:Category:Zombies|recurring theme]] in xkcd, particularly zombie scientists, which has also occurred twice before with {{w|Richard Feynman}} in [[397: Unscientific]] and {{w|Paul Erdős}} in [[599: Apocalypse]].

==Transcript==
:[Ponytail is looking up at a picture on the wall showing Marie Curie with a white hair bun. She seems to be standing in front of a laboratory table with samples strewn over the surface. Her arms are in front of her like she is working with these samples. A voice comes from off-panel (and is revealed in the next panels to be Zombie Marie Curie.]
:Ponytail: My teacher always told me that if I applied myself, I could become the next Marie Curie.
:Zombie Marie Curie (off-panel): You know, I wish they'd get over me.
:[Inserted panel mainly inside the first panel, but extending a bit it, with a close up of Ponytail who turns her face around swiftly towards the zombie, as indicated by two speed lines curving around her head, even breaking the panels frame.]
:Ponytail: Zombie Marie Curie!

:[Ponytail has turned towards Zombie Marie Curie, drawn as Hairbun, who is walking towards Ponytail in typical zombie fashion both arms stretched out, with a battered and weathered look Stuff is falling off behind her, presumably mainly earth from when she dug herself out of her grave, and she is leaving a trail of this behind her, and it keeps falling from both of her hands and her body.]
:Zombie Marie Curie: Not that I don't deserve it. These two Nobels ain't decorative. But I make a sorry role model if girls just see me over and over as the one token lady scientist.

:[Close up of Zombie Marie Curie holding a hand up. She clearly has two large pieces of earth stuck to her face, and her hair is in disarray even with the hair bun keeping it in place.]
:Zombie Marie Curie: Lise Meitner figured out that nuclear fission was happening, while her colleague Otto was staring blankly at their data in confusion, and proved Enrico Fermi wrong in the process. Enrico and Otto both got Nobel Prizes. Lise got a National Women's Press Club award.
:Zombie Marie Curie: They finally named an element after her, but not until 60 years later.

:[Zoom out to both Ponytail and Zombie Marie Curie both with their arms down.]
:Zombie Marie Curie: Emmy Noether fought past her Victorian-era finishing-school upbringing, pursued mathematics by auditing classes, and, after finally getting a Ph.D, was permitted to teach only as an unpaid lecturer (often under male colleagues' names).
:Ponytail: Was she as good as them?
:Zombie Marie Curie: She revolutionized abstract algebra, filled gaps in relativity, and found what some call the most beautiful, deepest result in theoretical physics.
:Ponytail: Oh.

:[Close up of Zombie Marie Curie.]
:Zombie Marie Curie: But you don't become great by trying to be great. You become great by wanting to do something, and then doing it so hard that you become great in the process.

:[Zoom out to both Ponytail and Zombie Marie Curie.]
:Zombie Marie Curie: So don't try to be the next me, Noether, or Meitner. Just remember that if you want to do this stuff, you're not alone.
:Ponytail: Thanks.
:Zombie Marie Curie: Also, avoid radium. Turns out it kills you.
:Ponytail: I'll try.

==Trivia==
*Marie Curie was later drawn in similar Hairbun style (but not with the zombie decay) in [[Thing Explainer]] in the article ''The pieces everything is made of'' (about the {{w|Periodic table}}), since she discovered two of the elements and had one element named after her, just like Lise Meitner.

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring real people]]
[[Category:Zombies]]
[[Category:Physics]]
[[Category:Math]]
[[Category:Science]]

599: Apocalypse

2022-05-04T01:31:21Z

172.68.110.141: Undo revision 234495 by X. K. C. D. (talk)

{{comic
| number = 599
| date = June 19, 2009
| title = Apocalypse
| image = apocalypse.png
| titletext = I wonder if I still have time to go shoot a short film with Kevin Bacon.
}}

== Explanation ==
This comic begins with the beginning of the {{w|Apocalypse}}, hence the title. It is depicted, properly, with a very dystopian color picture with several yellow burning {{w|meteors}} striking down from the blood red sky, towards a black, red, orange and yellow ground. The way the panels are drawn below makes a transition from this dark image to a normal comic, with the first normal panel being superimposed on the dark image.

In this image [[Beret Guy]] shouts out '''The apocalypse!''' And then he continues to explain what this will mean: ''The skies burn, the seas turn to blood, and the dead walk the earth!''

All three sentences are attributed to the apocalypse, but it seems that the first one about the sky burning, actually comes from a translation of one of the {{w|Nostradamus}} predictions which has, amongst others, been used to "{{w|Nostradamus_in_popular_culture#September_11.2C_2001|predict 9/11}}". In {{w|Revelation 16}} from the Bible about the {{w|Seven bowls}}, which are a set of seven plagues of God's wrath poured over the wicked towards the Apocalypse, the {{w|Seven_bowls#Second_Bowl|second bowl}} describes that ''{{w|Revelation_16#Structure|The Sea Turns to Blood}}''. The {{w|Universal resurrection|resurrection of the dead}} is from the biblical version of the Apocalypse, the {{w|Last Judgment}}.

After Beret Guy has announced this, he runs into [[Cueball]] who has heard part of this, but he is only interested in the last part and asks to check if he understood correctly that the dead will walk the earth. When this is confirmed Cueball becomes very busy.

He runs to his office and quickly writes a scientific math paper, then runs as fast as he can to the math department and get his colleagues to sign it. Then he runs to a cemetery where the dead are rising, finds the one he searched for, and asks the resurrected {{w|zombie}} if he is Erdős. When confirmed that he is indeed Erdős, Cueball asks him to sign the math paper.

{{w|Paul Erdős}} (26 March 1913 – 20 September 1996) was a Hungarian mathematician who (according to Wikipedia) published more papers than any other mathematician in history, working with hundreds of collaborators. His grave is in the Kozma Street Cemetery in Budapest.

There is an in-joke developed among mathematicians called the {{w|Erdős number}} (similar to a Bacon number for film actors, referenced in the title text, see below). By definition, Erdős has an Erdős number of 0. Everyone who has co-written a mathematical paper with Erdős has an Erdős number of 1. Everyone who collaborated with them (but not Erdős himself) is assigned an Erdős number of 2. In general, if ''k'' is the minimal Erdős number of all the people you've [https://paperell.com/ written papers] with, your Erdős number is ''k'' + 1. The Erdős number is the length of the shortest "chain" from you to Erdős.

Thanks to collaboration between mathematicians and other researchers, many people in science and medical research now have Erdős numbers. Not everyone has an Erdős number, though; people without any chain linking them to Erdős have an undefined Erdős number. For example, most people who are not mathematicians or scientists do not have Erdős numbers. Nor do mathematicians and scientists whose publications were written by themselves only with no collaborators.

By this trick Cueball thinks that he and his colleagues will now all have an Erdős number of 1. The joke is that he would be using his last few hours in this life to write a math paper just to improve his and his friends' Erdős numbers.

There are, however, many problems with his idea, even assuming the dead will walk the earth on that day. First of all, just having your name on a piece of paper with Erdős's signature does nothing for your Erdős number. It needs to be a {{w|Scientific_literature#Scientific_article|scientifically valid paper}}, published in a {{w|peer reviewed}} {{w|scientific journal}}. And given that the apocalypse is happening, there seems no time, chance or reason to publish any more math papers.

Even if there were time, it would not count for much to have someone sign a math paper they haven't even read, let alone had anything to do with the actual writing and research. The same would be true for the other five mathematicians who signed it. But of course many papers have coauthors who did not do much more than work in the same department as the person who actually wrote the paper (a sad but true fact). Presumably Cueball's friends assume that nobody will investigate whether they, or Erdős, truly participated in the writing and research of Cueball's paper.

Furthermore, even if it did count, they will not be able to take the paper with them into the afterlife (although since nobody has ever returned from the afterlife{{Citation needed}} we can't be certain of this), and thus since no one would have had time to read the paper, no one would know they had an Erdős number of 1. In the afterlife they could all say that they had such a number, but then again everyone else with such an interest could do the same, since no one could prove otherwise. Of course if you end up in the same part ({{w|Heaven}} or {{w|Hell}}) of the {{w|afterlife}} as Erdős he could confirm or deny the claim, but that would probably not help Cueball and his friends, since he could tell the truth about their paper. (Erdős was known for using an idiosyncratic set of slang terms, in which he described people who had stopped doing mathematics as having "died", whereas people who had died had "left".)

That the whole comic is about the Erdős number, and not just Erdős signature, is made clear in the title text which refers to a similar (and less esoteric) meme called "{{w|Six Degrees of Kevin Bacon}}", or simply Bacon numbers. This time, the chain's center is actor {{w|Kevin Bacon}}, and the links are formed by two people appearing in the same movie. Unlike Erdős, Kevin Bacon is not dead, so those of you wishing to get a Bacon number of 1 still have a chance.

In the title text Cueball thus wonders if there is still time for him to make a short film with Kevin Bacon, now he has used so much time on improving his Erdős number. Again, if the film hasn't been shown to the public it would not count for anything...

One of the mathematical scribbles appearing in panel 5 shows the square root of 163, which may be a reference to {{w|Ramanujan's constant}}.

[[403: Convincing Pickup Line]] has a parody of the Erdős collaboration graph.

Zombies are a [[:Category:Zombies|recurring theme]] in xkcd, particularly zombie scientists, which has also occurred both before with {{w|Richard Feynman}} in [[397: Unscientific]] and after with {{w|Marie Curie}} in [[896: Marie Curie]].

==Transcript==
:[The first panel is very large and shows a dark scene with one large meteor in front and four smaller in the background showering the darkened earth. They are all five black with yellow fire around them and a fire trail behind them, and all are flying from the top left corner and down towards right. The sky at the top is pitch black, but then the sky turns blood red under dark clouds. Two large mountain peaks, one almost pyramid shaped, are shown to the left and to the right there are two smaller peaks towards the distant horizon. The mountains and the ground around them are mainly black, but with red, orange and yellow streaks spread all over the black area beneath the mountain peaks, maybe indicating fire or lava, or reflections in water or blood. At the bottom right corner a normal white panel is superimposed on this apocalyptic image.]

:[The smaller panel at the bottom of the first is halfway over the first panel, haflway below, and only to the right of the middle of the first panel. Beret Guy is running towards left, with his arms raised in the air.]
:Beret Guy: The apocalypse! The skies burn, the seas turn to blood, and the dead walk the earth!

:[From here a normal sequence of panels in three rows begin beneath the second panel. This leaves a gap between the apocalyptic panel and the first row of regular panels, on the left side where the 2nd panel did not reach over. In this panel Beret Guy (coming from the right) finds Cueball.]
:Cueball: The dead what?
:Beret Guy: Walk the earth!

:[Cueball running right in a thin panel.]
:Cueball: I have to go.

:[Cueball sitting on a chair at a table scribbling vigorously and noisily with a pen on a paper. Mathematical symbols appear above Cueball's head, including a summation from i=0 to n, a logarithm of n and the square root of a number.]
:<big>∑</big>ni=0ik1/i log(n)
:√163
:''Scribble''
:''Scribble''

:[Cueball running right again, in a thin panel, pen and paper in hand.]

:[Cueball opening door with label:]
:Math Dept
:Cueball: The dead return!
:Cueball: Everyone, quick, get your names on here!

:[Cueball stand on the left side of a table looking left over his shoulder. Five people are lining up to sign the paper lying on the right side of the table. The first who signs with a pen is Blondie, then in line follows Megan, a Cueball-like guy, Ponytail and another Cueball-like guy who stand with one hand to his chin looking right, away from the other.]
:Blondie: At last!
:Guy looking right: I hope there's time!

:[Cueball running right in yet a thin panel, with pen and the paper flowing behind him.]

:[Cueball walks right with the paper and pen in his hand as he arrives at at a cemetery as revealed by an old worn sign. Scary sounds appear off-panel right.]
:Sign: Cemetery
:Rising dead (off-panel): ''Hurrghhh''

:[Cueball, still going right, arrives at a grave, pen in hand and the other hand almost outside the panel, but with a corner of the paper just visible. The grave has a large gravestone to the right and in front of it there is a Cueball-like guy rising up from the ground using his arms to push up on the base of the stone and the small pile of earth towards Cueball. The guy looks very worn, with dirt on his head and scratches on his cheek.]

:[Cueball bends a little down and offers pen and paper to the raised dead man who looks up at him when he is addressed.]
:Cueball: Paul Erdős?
:Erdős: Yes?
:Cueball: We need you to sign this.

==Trivia==
*This version of [[Blondie]] seems to be employed at a mathematical department on a university. It could thus also be [[Miss Lenhart]], but there is no proof that she is a teacher...

{{Comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Blondie]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Multiple Cueballs]]
[[Category:Comics featuring real people]]
[[Category:Math]]
[[Category:Zombies]]
[[Category:Comics with blood]]
[[Category: Research Papers]]

2609: Entwives

2022-04-20T14:40:44Z

172.68.110.141: /* Explanation */

{{comic
| number = 2609
| date = April 20, 2022
| title = Entwives
| image = entwives.png
| titletext = No, we actually do have a woman who's basically part of our fellowship. She lives in Rivendell, you wouldn't know her.
}}

==Explanation==
In {{w|The Lord of the Rings}}, the {{w|Ent|Ents}} are a species of tree-like humanoids, such as the one depicted in this comic. Part of the backstory of the Ents is that all of the women of their species (the Entwives that this comic is named for) left many years ago over a dispute with the male Ents, who have since been searching for them in an attempt to make amends and preserve the future of their species. The loneliness of the Ents' all-male society is considered a great tragedy in their culture.

This comic uses that plot point to satirically comment on the extreme gender imbalance of the cast of Lord of the Rings; when presented with the all-male Fellowship of the Ring, the Ent assumes that they must come from a culture afflicted by a similar tragedy. In reality, of course, the dwarves, elves, hobbits, and men all have a roughly even gender ratio, and the lack of women in the Fellowship is due not to cultural tragedy, but simply the author neglecting to include any female characters.

The clickable link leads to a [https://www.youtube.com/watch?v=mt2qCjL6-n4 video showing the singular scene where two women interact], which is there to emphasize how few women there are in the franchise. The inclusion of this clip may be a reference to the {{w|Bechdel test}}, a metric for judging the representation of women in a piece of media that requires to women to have a conversation about something other than a man. Whether this two-and-a-half-word exchange is sufficient to pass the test is debatable.

The title-text most likely refers to the character of Arwen; while important to the story, she is nowhere near on the level of the Fellowship, and even if she were, a single important woman wouldn't counterbalance the heavily male-centric storytelling. The way that the title text is phrased is a reference to the proverbial (and implicitly imaginary) "girlfriend in Canada," a trope in which a single character claims to have a girlfriend that their friends wouldn't know "because she lives in Canada," when in reality the reason that nobody else has met her is because she doesn't exist. {{w|Canada}} is one of the United States' two neighboring countries, making it theoretically a potentially plausible place for an American's long-distance girlfriend to live.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

[Ent Man stands to the left, facing right. Aragorn, Gimli, Legolas, and three hobbits stand to the right of Ent Man, facing him.]

Ent Man: Alas, there are no Ent women. The Entwives all vanished in the second age, during Sauron's war.

Aragorn: I'm so sorry.

Ent Man: And what about you all? Same story, I assume?

Aragorn: Huh? No, what do you mean?

{{comic discussion}}

2607: Geiger Counter

2022-04-15T20:23:27Z

172.68.110.141: /* Transcript */ typo

{{comic
| number = 2607
| date = April 15, 2022
| title = Geiger Counter
| image = geiger_counter.png
| titletext = At first I didn't get why they were warning me about all those birds sitting on the wire, but then I understood.
}}

==Explanation==
{{incomplete|Created by A CLICKING GEIGER COUNTER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is a simple {{w|pun}}. [[Cueball]] and [[Ponytail]] are standing in what looks to be a desert, and Cueball is holding a {{w|Geiger Counter}} in his hand. Cueball remarks that he did not understand why he was asked to carry a Geiger counter, but that it then "clicked" with him.

Geiger counters are devices used to measure the amount of {{w|radiation}} in an area. When a particle of ionizing radiation hits the sensor of a Geiger counter, it will give off a distinct "clicking" noise. The pun in this comic insinuates that cueball realized why he was asked to bring the Geiger counter when it clicked, indicating radiation nearby. In radioactive areas, it is usually a good idea to carry around some sort of radiation detector for safety reasons.

The title text is also a pun, since "I" stand under the birds on the wire (under-stood).

==Transcript==

{{incomplete transcript}}
:[Cueball and Ponytail are wearing hard hats and standing in what looks to be some sort of desert or rocky area. Cueball is holding a Geiger Counter in his hands.]
:Cueball: At first I was confused about why they wanted me to carry a Geiger Counter here, but then it clicked.

{{comic discussion}}

Talk:2606: Weird Unicode Math Symbols

2022-04-14T15:02:32Z

172.68.110.141:

Apparently, nobody knows what U+237C ⍼ means (https://ionathan.ch/2022/04/09/angzarr.html)
: For me it looks very like as designation of where electrical cable is burrowed. It should come with numbers near angle hands designating depth and offset from sign. But it just a guess, of course [[Special:Contributions/141.101.76.221|141.101.76.221]] 05:30, 14 April 2022 (UTC)

: There are at least four people on (https://news.ycombinator.com/item?id=31012865) who claim to have seen the symbol in the wild: German/Dutch proof by contradiction, diode with a gate, Finnish proofreaders mark indicating when and how to split a word, and indicating which way EM waves are polarized --[[Special:Contributions/162.158.62.180|162.158.62.180]] 11:42, 14 April 2022 (UTC)

: I think that is "larry potter" as the lightning symbol, and the L comes from the L shape the lightning is over imo. [[Special:Contributions/172.70.34.191|172.70.34.191]] 14:47, 14 April 2022 (UTC)Bumpf

Can someone add a column where we try to crowdsource a description for the "mathematical use of symbol" ?

I'm curious what those symbols actually mean, and the unicode titles don't give that much information.

I do not doubt that have enough math geeks on here to find the answer to most of then :-D

Thanks!
[[User:Flekkie|Flekkie]] ([[User talk:Flekkie|talk]]) 01:20, 14 April 2022 (UTC)

i agree w Flekkie's comment
[[User:Blue in real life|Blue in real life]] ([[User talk:Blue in real life|talk]]) 02:27, 14 April 2022 (UTC)

If you make edits, please don't immediately delete all of mine because you think yours are better. It shows you conflicting edits for a reason. Some explanations are nonsensical, like defining a smash product as the "result of dividing two product spaces." The smash product is specifically the quotient of the underlying spaces of two pointed spaces where points in the product spaces are identified if they contain either labeled point as an element. Other claims are simply mistaken. For instance, the ≝ symbol is used to introduce a definition, not to declare that the definition has been achieved in a proof. The claim that "A union on smash product appears to be one where the sets are nit isomorphic" is totally meaningless. The symbol ⩩ is not merely decorative but is intended as a supplemental math symbol like all the others. I couldn't track down its purpose. The APL symbol description somehow never bothers to mention APL. This is all very cursory, which is fine, but just please don't delete my work while doing it. [[Special:Contributions/172.70.130.5|172.70.130.5]] 04:15, 14 April 2022 (UTC)
:I'm done, page is yours. I'd been working on it for an hour and every time I tried to save, a new edit came in. I did my best to reconcile them but by the fifth I just saved a copy of what was there and pasted mine over. I immediately got to work on recovering what I had pasted over as indicated in the edit comment and like I said, I'm done. I've merged to the best of my ability and have no more interest in this page.
:--[[User:FrankHightower|FrankHightower]] ([[User talk:FrankHightower|talk]]) 04:37, 14 April 2022 (UTC)
::I'm very sorry if I was one of those who stepped on your edits. I was originally trying to fix brokenness in the table. ^^^^^ ≫ ^ is the symbol for preferring many small edits over not saving your work often in a batch-mode collaborative editing environment. [[Special:Contributions/172.70.207.8|172.70.207.8]] 04:55, 14 April 2022 (UTC)

:: Don't worry about it, idk why I was so upset. It's that feeling you get when you click "save" and then suddenly it's gone. If anything's still missing, I'll just restore it. [[Special:Contributions/172.70.131.106|172.70.131.106]] 05:41, 14 April 2022 (UTC)

I wish we had as much research on ⧍ and ⩩ as we have for ⍼. [[Special:Contributions/172.70.207.8|172.70.207.8]] 05:16, 14 April 2022 (UTC)
: No clue what those are for. The first is a triangle with serifs? The triangle symbol (not capital delta) is often used in geometry to represent a triangle, but why in the world would you give a geometric figure serifs? I think I may have seen the triple cross-hatch somewhere, but I couldn't say where. Maybe it's the chess commentary symbol for being mated so badly it's embarrassing. [[Special:Contributions/172.70.131.106|172.70.131.106]] 05:41, 14 April 2022 (UTC)
:: I'm guessing what must have happened is the [https://decodeunicode.org/en/u+2A00 code page in question] was filled in by a typographer with more graphic design than mathematical experience, who likely added made-up "missing" symbols as the design-logical extensions of the symbols they were given, presumably to be on the safe side in case they had what appeared to be a possibly incomplete set. There are some awesome ones in there, like "⩐" TEST-TUBE PARTHENOGENISIS, and "⨻" THE ILLUMINATI IS DEAD. [[Special:Contributions/162.158.255.171|162.158.255.171]] 06:07, 14 April 2022 (UTC)
: The ⧍ character has the same origin as ⍼, namely that they were both part of ISO/IEC TR 9573-13 with no explanation given. You can find it in some old charts online, like here: [https://www.w3.org/TR/REC-MathML/chap6/ISOAMSBe2.html], under `trisb`/codepoint E27E. [[User:Ionchy|ionchy]] ([[User talk:Ionchy|talk]]) 07:03, 14 April 2022 (UTC)
:: I am sure that I have seen maps with such a symbol used for campsites, and without the bold strokes of the top sides as the National Park Service draws it. I haven't found any yet, but I have found one without the center base -- like _/\_ -- on a 1960s era map. [[Special:Contributions/172.69.134.131|172.69.134.131]] 07:07, 14 April 2022 (UTC)
: As for ⩩, the character just before it in the Unicode code chart [https://www.unicode.org/charts/PDF/U2A00.pdf], ⩨, has the text "identical and parallel to", so it's possible the horizontal lines in this one also means "identical to". I don't know what three vertical lines mean though, and in Unicode there's three (!) different characters with similar glyphs: U+2980 ⦀, U+2AF4 ⫴, and U+2AFC ⫼. [[User:Ionchy|ionchy]] ([[User talk:Ionchy|talk]]) 07:28, 14 April 2022 (UTC)
:: Identical both vertically and horizontally? [[Special:Contributions/172.69.134.131|172.69.134.131]] 07:32, 14 April 2022 (UTC)
:: I found one suggestion that the dodecathorp should be used to refer to very big numbers...[[Special:Contributions/172.69.79.223|172.69.79.223]] 08:33, 14 April 2022 (UTC)

Apparently, Randall reads Hacker News like the rest of us... --[[Special:Contributions/172.68.110.141|172.68.110.141]] 09:38, 14 April 2022 (UTC)

Did you know that ⩩ was a logo of the Romanian fascist group Iron Guard?[[Special:Contributions/172.68.238.67|172.68.238.67]]
:Wow. "Saint Michael's Cross, the ({{w|Iron Guard}}) movement's symbol designed by Codreanu." I prefer the 4x4 tic-tac-toe board.... [[Special:Contributions/172.69.33.181|172.69.33.181]] 12:29, 14 April 2022 (UTC)

Not that I have special knowledge (above aspiring-polymath level), but for "Rightwards Arrow Above Reverse Almost Equal To" and its leftwards sibling (the current suggestion being that it's an assignment of an approximation) I'd posit that it's a directional approximation specific to chaotic systems. For a precise a=b in a system where small changes to one side can effect large changes in the other, uncertainty or deliberate approximation of either of them ''may'' still map well enough to the value across the desired ≈ relationship, but that is only acceptably so unidirectionally. Hence (and I wouldn't know which would be the better convention) the arrow depicts the direction of either the dependence or the more dominant option, whichever it is that almost-ties the values tovether. (I also really ought to check what the ''reverse'' almost-equal-to sign is used for, it could be radically different from the 'forwards' version in some field, for which the directionality might even be trivially understood by context.) [[Special:Contributions/172.70.91.36|172.70.91.36]] 11:25, 14 April 2022 (UTC)
:Any sources? I found several papers on the topic you describe naively searching on those keywords, and while they are packed with notation, I couldn't find any arrows or approximate equality signs, let alone any sort of composition of the two. [[Special:Contributions/172.69.33.51|172.69.33.51]] 12:47, 14 April 2022 (UTC)
::No sources except in my (above-IP's, just to confirm) head. It's just something I ''might'' use it for, if let loose on a whiteboard for some reason, not something for which I've seen it used. It's a situation I've encountered often enough in my own amateur numerical analysis, but under self-taught/self-experimenting circumstances where I was probably just (inefficiently) re-inventing the wheel. And if I've been commenting code (itself strings of conventional syntactical symbols), as a usually futile attempt to remind future-me what I was doing, I would have been using longhand to describe what I was either basing my functions on or actually asking them to test... So no surprise that a paper-search didn't match much of my description. ;) [[Special:Contributions/172.70.162.155|172.70.162.155]] 14:39, 14 April 2022 (UTC)

No idea how Randall got that wrong, but U+2A50 (⩐) is totally catching a snowflake with your tongue. [[Special:Contributions/172.68.110.141|172.68.110.141]] 15:02, 14 April 2022 (UTC)

Talk:2606: Weird Unicode Math Symbols

2022-04-14T09:38:24Z

172.68.110.141:

Header text

2022-01-27T23:24:22Z

172.68.110.141: Fix "Latencey" typo

*This page is part of the [[Design of xkcd.com]] explanation.
*The header text is part of the [[Design_of_xkcd.com#Header|xkcd Header]].
*The header text is often [[#Changes to the header text|changing]] when Randall has news to tell.
**But when this news wears off the page usually returns to the '''go-to header text''' which is:
***'''xkcd updates every Monday, Wednesday, and Friday.'''
***It was last changed back to it on [[#2022-01-08 - Back to standard text|2022-01-08]].
****At that time it was almost three years since it was used last time.
**See more about the [[#Current header text|current header text]] below.
{{xkcdmeta}}
==Current header text==
*The current header text will be the top of the [[#Changes_to_the_header_text|list of changes]], if this page is kept up to date...
*Usually the header text is the same for all comics.
**But for certain comics there may be a reason to change the text permanent and as long as that is active they will not change along with the other.
**See [[#Unique header text|Unique header text]]

==Unique header text==
*Some comics have their own version of the header text that do not change.
**Only when the comic is on the front page, will it also be the main header text of xkcd.
**'''Put newest comic at the top.'''
**Here below are examples of that:

===Checkbox===
*[[2445: Checkbox]]
**This comic's header mentions the people who helped put it together.
***It was on the front page from Thursday [https://web.archive.org/web/20210401232108/https://xkcd.com/ 2021-04-01] until Monday [https://web.archive.org/web/20210405130031/http://xkcd.com/ 2021-05-01], until the new comic was released on Monday.
**The text:
***This comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/fadinginterest Patrick], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin Cotrone], [https://twitter.com/wirehead2501 Kat], and [https://twitter.com/dyfrgi Michael Leuchtenburg].
**It thanks those that helped Randall create that years [[:Category:April fools' comics|April fools' comic]].
***All have a link to their name, the first with a personal home page, the other six with a link to their Twitter account. Five of those also helped with the previous April Fools' comic, see above.
**Since this header was related only to the Fools' comic, it was removed from the front page header, when the next comic was released, here from the day after that release Tuesday [https://web.archive.org/web/20210406143023/http://xkcd.com/ 2021-04-06].
**But it stayed up as one of the permanent different headers on this comic, as seen two days later on [https://web.archive.org/web/20210407203547/https://xkcd.com/2445/ 2021-04-07].
**See the comic on xkcd {{xkcd|2445}}.

===Collector's Edition===
*[[2288: Collector's Edition]]
**This comic's header mentions the people who helped put it together.
***It was on the front page only for about a day around April 3rd and [https://web.archive.org/web/20200404014814/http://xkcd.com/#-370,-277vApril 4th 2020].
**The text:
***Today's comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin], [https://www.instagram.com/fading_interest/ @fading_interest], [https://twitter.com/wirehead2501 Kat], [https://twitter.com/zigdon @zigdon], and Christopher Night.
****All names have links except the last.
**It thanks those that helped Randall create the 2020 [[:Category:April fools' comics|April fools' comic]], which had taken two extra days before it was released due to the complex nature of the comic.
*Due to the delay the next comic, [[2289: Scenario 4]], was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!
**Since this header was related only to the Fools' comic, it was removed from the front page header, when the next comic was released, but it stayed up as one of the permanent different headers on this comic
**See the comic on xkcd {{xkcd|2288}}.

=== Seven Years===
*[[1928: Seven Years]]
**[http://web.archive.org/web/20171214171157/https://xkcd.com/ 2017-12-14]
**It was released as a response to another cancer diagnosis, this is explained in the [[Design_of_xkcd.com#Header_text|Header text]] which has replaced the standard ''xkcd updates every Monday, Wednesday, and Friday.'' The new one is this one, with the active link included:
**The text (with link):
***Becky Beaton, sister of fellow cartoonist Kate Beaton, has also been diagnosed with cancer. You can support her treatment [https://www.youcaring.com/beckybeaton-1008390 here].
**{{w|Kate Beaton}} is the creator of the web comic [http://www.harkavagrant.com/ Hark! A Vagran].
***Although this comic is not one on Randall's list of ''[[Design_of_xkcd.com#Comics_I_enjoy|Comics I enjoy]]'', he is clearly much influenced by another cancer diagnosis among someone in his own creative field.below.
**On [https://web.archive.org/web/20190817141450/https://www.xkcd.com/1928/ 2019-08-17], close to two years later, the message was still there and also [https://web.archive.org/web/20211226120634/https://xkcd.com/1928/ 2021-12-26] just past four years later.
***There was the possibility that it would be removed, when the support page was discontinued...
***But as that already happened before [http://web.archive.org/web/20181106124430/https://www.youcaring.com/beckybeaton-1008390 2018-11-06] it seems like it will be there to stay.
***Last archived version was from [http://web.archive.org/web/20180305022301/https://www.youcaring.com/beckybeaton-1008390 2018-03-05].
***Randall has previously done something similar for another friend, Emiliy, but [[#2014-11-27_-_Help_Emily|that header]] was not made permanent.
**See the comic on xkcd {{xkcd|1928}}.

===ISS Solar Transit 2===
*[[1830: ISS Solar Transit 2]]
**[https://web.archive.org/web/20170428041338/https://xkcd.com/ 2017-04-28]
**This header links back to [[1828: ISS Solar Transit]], a comic with the same joke setup released on the Monday of the same week
**See the comic on xkcd {{xkcd|1830}}.

===Meteorite Identification===
*[[1723: Meteorite Identification]]
**Randall realized that his comic was almost a copy of some other person. And he has since then acknowledged this on the comics specific page see more [[1723: Meteorite Identification#Trivia|here]].
**At the time of this post, in the newest saved version on the archive from [http://web.archive.org/web/20161010215516/http://xkcd.com/1723/ 2016-10-10] it is still there and says:
***Note: Jolyon, founder of [http://www.mindat.org/ mindat.org], made a similar chart way before me!
**See the comic on xkcd {{xkcd|1723}}.

===Substitutions 3===
*[[1679: Substitutions 3]]
**This was the third installment of Substitutions and as he did with [[#Substitutions 2|the second]] linking to the first and telling about browser extensions for this he did the same with this one:
**The text:
***(Previously: {{xkcd|1288|Substitutions}} and {{xkcd|1625|Substitutions 2}})
***Note: There are various [https://chrome.google.com/webstore/detail/replacerator/gaajhenbcclienfnniphiiambbbninnp?hl=en browser extensions] for this.
**It was on the main page while the comic was up, for instance here on [https://web.archive.org/web/20160512102325/http://xkcd.com/ 2016-05-12].
**See the comic on xkcd {{xkcd|1679}}.

=== Garden===
*[[1663: Garden]]
**This comic had a header text to help people use the comic when it came out.
**For some time this text was the main header text, but after a while is disappeared from the main header, but remained as the header for Garden.
***See more [[xkcd_Header_text#2016-04-04_-_Protip_on_Garden|below]] or on the Garden page [[Garden#Header_text_after_release|here]]
**Today and as of the newest saved version on the archive from [http://web.archive.org/web/20161231231600/http://xkcd.com/1663/ 2016-12-31] it is still there and says:
***Protip: If you don't like how your garden is growing, you can click to prune it.
***You can copy the URL to share your garden. From other browsers, it will be view-only.
**See the comic on xkcd {{xkcd|1663}}.

===Substitutions 2===
*[[1625: Substitutions 2]]
**This was the second installment of Substitutions and Randall links to the first and tells about browser extensions for this:
**The text:
***(Previously: {{xkcd|1288|Substitutions}})
***Note: There are various [https://chrome.google.com/webstore/detail/xkcd-substitutions/jkgogmboalmaijfgfhfepckdgjeopfhk?hl=en browser extensions] for this.
****He did the same when [[xkcd_Header_text#Substitutions_3|Substitutions 3]] came out, linking to the two previous.
**It was on the main page while the comic was up, for instance here on [https://web.archive.org/web/20160104171722/http://xkcd.com/ 2016-01-04].
**See the comic on xkcd {{xkcd|1625}}.

===United Shapes===
*[[1079: United Shapes]]
**The header was unique for this comic on the day it came out: [https://web.archive.org/web/20120709045709/http://xkcd.com:80/ 2012-07-09].
**The text:
***There's a larger version of this map [http://xkcd.com/1079/large/ here] (Colorado is [http://xkcd.com/1079/colorado/ here]).
***It's also available as a [https://web.archive.org/web/20120709045709/http://store.xkcd.com/xkcd/#StateMap poster].
**The text was never on other pages:
***Before US was released, also on [https://web.archive.org/web/20120709004956/http://www.xkcd.com/ 2012-07-09] the comic [[1078: Knights]] was on the main page, with the previous promotion of the store.
***The US version was still on the front the day after [https://web.archive.org/web/20120710063424/http://xkcd.com/ 2012-07-10].
***But the same day [https://web.archive.org/web/20120710114846/http://xkcd.com/1078/ 2012-07-10] the page for Knights did show a new header, which may only have been active on other pages than the front on this day...
****Here is another page from [https://web.archive.org/web/20120710095644/http://xkcd.com/1070/ 2012-07-10] with [[1070: Words for Small Sets]], that was also saved that day, so this was on the top of all other comics, except the front page.
**There are simply no version of the front page from the 11th and 12th of July 2012. But from other pages it can be shown that from the 11th there was a difference.
***On [https://web.archive.org/web/20120711223349/http://xkcd.com/1078/ 2012-07-11] on the page for Knights and for instance from the same day on page number [https://web.archive.org/web/20120711223339/http://xkcd.com:80/1077 1077] [[1077: Home Organization]] there is the same but new header, different than the one Knights had both two days before and the other one from the day before.
***And also on [https://web.archive.org/web/20120711123734/http://xkcd.com:80/1079/ 2012-07-11] the numbered page {{xkcd|1079}} for US displays a mix of this new and the unique version of the header text.
****It left our the part about Colorado and moved the bottom line up so the unique part is written in one line (that may still take up two lines as the text will spill over, (maybe just in some browsers?)
****And then it added the two lines of header text that was on all the other pages (presumably also the front page, but that was first proved with the version from [https://web.archive.org/web/20120713154207/http://xkcd.com/ 2012-07-13]).
****And this is the version still shown on {{xkcd|1079}} today, even though the bottom lines was a normal header that was supposed to disappear.
**The final text that is still on US today:
***There's a larger version of this map [http://xkcd.com/1079/large/ here]! It's also available as a [https://store.xkcd.com/collections/posters/products/united-shapes-poster poster].
***New: [https://what-if.xkcd.com/1/ what-if.xkcd.com]: abusing science to answer hypothetical questions.
***I'll answer a new reader question every Tuesday.
****Here above the link has been updated to the one in the current version, where as the above link in the original version, that is now a dead link, has been directed to an archived version of the stores poster.
****The link the new part is to the very first [[what if]] post {{what if|1|Relativistic Baseball}} which was released on 2012-07-10, the day after US was released, but before the next comic [[1080: Visual Field]] was released on 2012-07-11.
*****There are no version of comic {{xkcd|1080}} archived while it was on the front page, so it is not possible to tell what the front page looked like on the 11th and 12th of July. But best guess is that it looked like that on Knight shown above from the 11th.
**The first version was on the main page while the comic was up.
***Maybe there was a time with the final version on the front page, but seems like Randall put the new header text there in hand, and forgot to delete it after, so he probably first changed it when the new comic came out.
***Since the new header was important, promoting his new ''what if'' blog, he likely did not wish to have a fairly new page (maybe even on the front page on the 10th) without the reference. Also he did not wish to remove the link to the poster in the store.
***But this makes it a special unique header, as a relic from the past header text is left together with the text that was supposed to be permanent. It should have been deleted when the link to ''what if'' 1 was removed.
**See the comic on xkcd {{xkcd|1079}}.

===Umwelt===
*[[1037: Umwelt]]
**It has a permanent promotion of the store already from the release day on [https://web.archive.org/web/20120401151639/http://xkcd.com:80/ 2012-04-01]:
**The unique text:
***You can get posters, prints, and t-shirts in the [https://store.xkcd.com/ xkcd store].
**It stayed on the front page while this comic was the most recent, so for instance also two days later on [https://web.archive.org/web/20120403223453/http://www.xkcd.com/ 2012-04-03]
***There was a different header on other comics even while this comic was on the front page with the unique text. See [[xkcd_Header_text#2012-03-28_-_Visiting_Newport_News|Visiting Newport News]].
**See the comic on xkcd {{xkcd|1037}}.

===s/keyboard/leopard/===
*[[1031: s/keyboard/leopard/]]
**In response to the idea of having you browser replace keyboard with leopard a reader made a script that could do just that.
**Randall seem to have gotten this script before release (or at least on the day of release) as it was already the header text on [https://web.archive.org/web/20120319130702/http://xkcd.com/ 2012-03-19] the day the comic was released.
**The unique text is:
***A helpful reader has provided an [https://userscripts.org/scripts/show/128626 s/keyboard/leopard/ user script].
****The link does not go anywhere useful any longer, but here is the archived version of the link from two days after the release of the comic on [https://web.archive.org/web/20120321174019/http://userscripts.org/scripts/show/128626 2012-03-21]
**It was never changed on the other comics so was only on the front while this comic was up until 2012-03-21
***Here also shown on the second day it was up on its own page on [https://web.archive.org/web/20120320143916/http://xkcd.com:80/1031/ 2012-03-20].
**The next comic [[1032: Networking]] came out on [https://web.archive.org/web/20120321205835/http://xkcd.com:80/ 2012-03-21] and here the header text has returned to what it was before the leopard comic: [[xkcd_Header_text#2012-03-12_-_xkcd_Holistic_Browser|xkcd Holistic Browser]].
***Here are examples from dates around this showing it was not used on other pages:
****The last archived version of the front page from before the 19th was this version from [https://web.archive.org/web/20120317121834/http://xkcd.com:80/ 2012-03-17], but here is an example from [https://web.archive.org/web/20120318153256/http://xkcd.com:80/1030/ 2012-03-18] (from comic [[1030: Keyed]]), the day before leopard comic came out.
****Both on [https://web.archive.org/web/20120319174700/http://xkcd.com/1030/ 2012-03-19] (from comic [[1030: Keyed]]) and on [https://web.archive.org/web/20120320191039/http://xkcd.com:80/1012 2012-03-20] (from comic [[1012: Wrong Superhero]]) during the time leopard was up, the header text currently in used was still shown.
**See the comic on xkcd {{xkcd|1031}}.

===Money===
*[[980: Money]]
**Randall notes his thoughts about making it and makes a promotion of the poster.
**The unique text for Money is:
***This one was fun (and exhausting) to make.
***There's a poster of it in the [https://store.xkcd.com/products/money-poster store]!
****It is both at the oldest stored version from [https://web.archive.org/web/20120404110059/http://xkcd.com:80/980 2012-04-04] and the newest at time of editing [https://web.archive.org/web/20220108132250/https://xkcd.com/980/ 2022-01-08].
**See the comic on xkcd {{xkcd|980}}.

===Na===
*[[851: Na]]
**After Randall made this comic, he realized he could have "made it better" and changed the header text to:
***I can't ''believe'' I forgot Hey Jude.
***I don't get do-overs, but I couldn't resist making [https://xkcd.com/851_make_it_better/ a fixed version].
**See more about it in that comics [[851:_Na#Trivia|trivia section]].
**See the comic on xkcd {{xkcd|851}}.

===House of Pancakes===
*[[472: House of Pancakes]]
**This comic's header notes its status as a parody:
***(Today's comic is a parody of [https://www.amazon.com/House-Leaves-Mark-Z-Danielewski/dp/0375703764 House of Leaves].)
**Only on the days this comic was the newest was this header featured on the front page of xkcd for instance as seen here the day after release on [https://web.archive.org/web/20080906103932/http://www.xkcd.com/ 2008-09-06].
***But it was only on this comic. The commercial for his new t-shirt was on all the other pages, also on [https://web.archive.org/web/20080906103932/http://www.xkcd.com/ 2008-09-06] and presumably returned to the front page with the next comic. But there is a gap in the archive after this comic.
**See the comic on xkcd {{xkcd|472}}.

==Changes to the header text==
*The header text changes often.
**Here these changes can be listed
**Begin with the date of the web archive link and make the date a link.
**Link to the comic that was on the front page when the text changed
**Then describe the changes and put in text if possible
**Also the comic that was the last to feature a message would be interesting to have below the other data.
**Put the newest (current) version at the top.

===2022-01-10 - Standard text with countdown===
*[https://web.archive.org/web/20220110183238/https://xkcd.com/ 2022-01-10].
**[[2565: Latency]] was still up when the [[Countdown in header text]] was added.
**The text was still the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
**But a countdown was added. This was inserted in a rectangular box, placed at the end of the standard header text.
***In some browsers the box forces the last word "Friday" to jump down to the next line.
**Inside the box the following time was displayed in the version in the link:
***20d 20h 27m
****This clock will also count down every minute, although it will return to the time at the time of archive when reloaded!
****While this was edited into this wiki the time had changed to 20d 19h 12m. So it was a very fresh download in the web archive, only about 1 hour old when it was updated to this wiki.
****The minutes change without refreshing the page, and follows this editors computers clock exactly, so it will end at 59 minutes, not at a full hour.
***It looks like it started on [https://munvoseli.github.io/xkcd-countdown/ 01-10 17:00 UTC].
****A calculation shows that this countdown will reach zero on Monday 2022-01-31 at 14:59 (2:59 PM) {{w|UTC}}.
****This will be at 9:59 (9:59 AM) in [[Randall]]'s home town
*****Maybe it will switch to seconds for the last minute to make it switch are 15:00 UTC 10:00 in Boston?
****From that it can be deduced that the count started at 20d 21h 59m
*****The first image on the archive thus came 1h 32m after the count began.
**At [https://web.archive.org/web/20220111153818/https://xkcd.com/ 2022-01-11] a diagonal black bar appeared in the lower left-hand corner of the countdown box.
***After that the [[Countdown in header text]] page was created and any further development on the count down will be mentioned on that page.


===2022-01-08 - Back to standard text===
*[https://web.archive.org/web/20220108044654/https://xkcd.com/ 2022-01-08].
**[[2565: Latency]] came out around the time the new header text appeared, on a Friday!
**The text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**This was the first time since [[#2018-11-07 - Back to standard text|2018-11-07]] that the text had changed back to that, and at that time it lasted until 2019-02-05.
***That is 1067 days (less than a month short of three years) without the standard text! (Can it be called standard anymore?)
**It was only left in the complete standard version until [https://web.archive.org/web/20220109030513/https://xkcd.com/ 2022-01-09] when Latency was still on the front page.
***Then the next day a [[#2022-01-10 - Standard text with countdown|countdown]] was added to it.
****That was after the weekend on Monday but before the Monday comic came up.
****So only during the weekend was it normal standard header text.

===2021-12-20 - What If in stock===
*[https://web.archive.org/web/20211220211220/https://xkcd.com/ 2021-12-20].
**[[2557: Immunity]] came out around the time the new header text appeared.
**The text:
***For anyone trying to find What If? this year, it's in stock at [https://www.barnesandnoble.com/w/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-randall-munroe/1118864093 Barnes & Noble], [https://m.booksamillion.com/p/What-If/Randall-Munroe/9780544272996 Books-a-Million], and [https://bookshop.org/books/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-9781483041827/9780544272996 Bookshop]
**Each store name is a link to the corresponding store's page for [[what if|what if?]].
*It was last seen on [https://web.archive.org/web/20220106100957/https://xkcd.com/ 2022-01-06] when [[2564: Sunshield]] was up.

===2020-06-03 - Black Lives Matter===
*[https://web.archive.org/web/20200604003700/http://xkcd.com/ 2020-06-03].
**[[2315: Eventual Consistency]] came out as a new header text was finally inserted after almost two months without one.
**Cueball is standing to the left and speaks a single line of text: "Black Lives Matter"
**To the right is a gray link button with text: "[https://www.joincampaignzero.org/ How To Help]."
**As always, the entire image (which is only below the xkcd logo) is a link
***The button is thus not needed, but it will also work when clicking the location of the button.
**The link goes to [https://www.joincampaignzero.org/ Join Campaign Zero].
***{{w|Black Lives Matter}} is a loose, grassroots, decentralized confederation of groups and individuals advocating for racial justice. It arose in 2013 after the acquittal of {{w|George Zimmerman}}, who took the life of {{w|Trayvon Martin}}.
***Randall's featuring Black Lives Matter came on the heels of the {{w|Killing of George Floyd}} on May 25th 2020, which had sparked {{w|George Floyd protests|protest in the US}}
***Floyd died while saying "{{w|I can't breathe}}," which was already used due to other Black men's killings, the first was from the {{w|Killing of Eric Garner}}, back in 2014.
*It stayed like this until [https://web.archive.org/web/20200616114945/https://xkcd.com/ 2020-06-16] when [[2320: Millennium Problems]] was up.
**Then on [https://web.archive.org/web/20200617131438/https://xkcd.com/ 2020-06-17] the link changed to [https://blacklivesmatter.com/ Black Lives Matter]. [[2320: Millennium Problems]] was still on the front page on that day.
*On April 1st 2021 the front page header changed to mention who made the April Fools' comic.
**But this was only for this comic [[#Checkbox|Checkbox]].
**The rest of the pages kept the BLM header and it returned to this on the front page once the next comic was released on April 5th. At that time it will have been up for 13 months, making it the longest header different from the standard header.
*It was last up on [https://web.archive.org/web/20211219202204/https://xkcd.com/ 2021-12-19] when [[2556: Turing Complete]] was on the front page.
**At that time it had been up for 564 days or 1,5 year plus 16 days! This is most likely a record.

===2020-04-05 - Empty header===
*[https://web.archive.org/web/20200405042955/https://xkcd.com/ 2020-04-05].
**[[2289: Scenario 4]] came out and the header belonging to the previous comic was removed.
**But no new header was inserted. Not even the go to [[#Header text|Header text]] about the release days of xkcd.
***Since the previous header was related only to the [[:Category:April fools' comics|April fools' comic]] [[2288: Collector's Edition]], and that had stopped the promotion of the [[How To]] book, after first experiencing problems with it's release, it seems Randall forgot what he usually put in the header.
*It stayed empty like this until [https://web.archive.org/web/20200602213017/https://xkcd.com/ 2020-06-02] when [[2314: Carcinization]] was on the front page.
**So almost two month without a header. This had not happened before.

===2020-04-04 - Put together by===
*[https://web.archive.org/web/20200404014814/http://xkcd.com/ 2020-04-04].
**[[2288: Collector's Edition]] came out and the header changed.
**The text:
***Today's comic was put together by [https://chromakode.com/ Max Goodhart], [https://twitter.com/Aiiane Amber], [https://twitter.com/bstaffin Benjamin Staffin], [https://twitter.com/cotrone Kevin], [https://www.instagram.com/fading_interest/ @fading_interest], [https://twitter.com/wirehead2501 Kat], [https://twitter.com/zigdon @zigdon], and Christopher Night.
****All names have links except the last.
**It thanks those that helped Randall create this years [[:Category:April fools' comics|April fools' comic]], which had taken two extra days before it was released due to the complex nature of the comic.
*Due to the delay the next comic, [[2289: Scenario 4]], was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!
**Since this header was related only to the Fool's comic, it was thus removed from the general header, but it stayed up as [[#Collector.27s_Edition|one of]] the permanent [[#Unique_header_text|unique header texts]].
***However, when it was removed from the general header, the header was left empty.
***Unlike some other headers that stayed on a given comic, this one was on all comics for the duration of the time it stayed on the front page, see for instance the previous comic on [https://web.archive.org/web/20200403232031/https://xkcd.com/2287/ 2020-04-03].

===2020-04-02 - Technical Reasons===
*[https://web.archive.org/web/20200402234828/https://xkcd.com/ 2020-04-02].
**[[2287: Pathogen Resistance]] was up when the header changed.
*Randall turned out to, again, have problems with his complicated and interactive [[:Category:April fools' comics|April fools' comic]] for 2020.
**The text:
***Note: For technical reasons Wednesday's comic will be posted Thursday instead. Apologies for the delay!
*This finally stopped the promotion of the [[How To]] book.
**It had then been part of the header for well over a year since [http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06].
*It stayed up a day longer than planed as the fool's comic, [[2288: Collector's Edition]] was first released on Friday, so the note was still up on [https://web.archive.org/web/20200403012612/https://xkcd.com/ 2020-04-03].
**[[2287: Pathogen Resistance]] thus stayed two extra day on the front page, and the third comic of that week, [[2289: Scenario 4]] was released already the day after the Fool's comic, even though it was thus [[2289:_Scenario_4#Trivia|on a Saturday]]!

===2020-01-16 - How To explores - again===
*[https://web.archive.org/web/20200116190038/https://xkcd.com/ 2020-01-16].
**[[2255: Tattoo Ideas]] was still up when the header changed.
**The ongoing promotion of the book continued but here more than three weeks after Christmas the reference to Christmas was removed.
**The header then returned to the one from before Christmas:
***[[#2019-11-22 - How To explores|How To explores]] - see that for all other details.
*It was last up on [https://web.archive.org/web/20200401221435/https://xkcd.com/ 2020-04-01] when [[2287: Pathogen Resistance]] was on the front page.
**It was the problems with [[:Category:April fools' comics|April fools' comic]] of 2020 that finally stopped the promotion of the [[How To]] book.
**It had then been part of the header for well over a year since [http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06].

===2019-12-02 - Into Science===
*[https://web.archive.org/web/20191202223745/https://xkcd.com/ 2019-12-02].
**[[2236: Is it Christmas?]] came out when the header changed. Fitting as the change is about Christmas list.
**Still promoting the new [[How To]] book, continuing to make the image a link to the [https://xkcd.com/how-to/ How To book] page on xkcd.
***The links below to order are the same as in the previous header.
***Actually most of the header stays the same with the same four images and the same layout. But the text above has changed completely and the two main text sections between the drawings has changed but only slightly. The description of the images is thus left out, see below. Only new thing is that there are now two red circles connected with a red arrow. The first circle is around the word How To at the end of the first text with the arrow going from that circle to the second circle drawn around the picture of the book.
**The text:
***Is there someone on you Christmas list who's into science? They might like my new book '''''How To'''''
***It explores ridiculous ideas for applying scientific research to everyday problems...
***...And illustrates what would happen if you tried them.
***''Boom''
***You can get it here:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
*It was last up on [https://web.archive.org/web/20200115155040/https://xkcd.com/ 2020-01-15] when [[2255: Tattoo Ideas]] was on the front page.

===2019-11-22 - How To explores===
*[https://web.archive.org/web/20191122214439/https://xkcd.com/ 2019-11-22].
**[[2232: Hotel Room Party]] was up when the header changed. It most likely changed when the comic appeared. Earlier on that day it was the previous header over the previous comic.
**Still promoting the new [[How To]] book, here again making the image a link to the [https://xkcd.com/how-to/ How To book] page on xkcd, after it previously was a link to where to listen to the audio book.
***The links below to order returns to the same as in the header before the previous header with links to audio books, except that the link to an exclusive edition has been removed.
***The header consist of an image with text above five small drawings with two text parts in between them. To the left is the closed How To book which is black with a blue readable title, How To, and unreadable white text below this as well as below the unreadable blue author name, which are below the image. The image shows Cueball putting in a light-bulb with drones under each foot while Megan, holding a ladder, and White/Black Hat are looking up at him. To the right of the book is a drawing of Ponytail pole-vaulting with two black helium filled balloons. Next to her is the first text segment. Then after that is the drawing, seen before in the header text, of a truck towing a house up a steep hill. This truck goes above the second text segment, with Cueball somersaulting above the text. Furthest right, above and just right of the text is an explosion with the sound written inside. Below the header image is some black text and then the links to where to get it as regular blue link text.
**The text:
***My new book '''''How To''''' explores the science behind spacecraft heat shields, butterfly metabolisms, and land border surveys...
***...By imagining ridiculous ideas for applying the research to you everyday life...
***...And illustrating what would happen if you tried them.
***''Boom''
***You can get it here:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
*It was last up on [https://web.archive.org/web/20191201191025/https://xkcd.com/ 2019-12-01] when [[2235: Group Chat Rules]] was on the front page.

===2019-11-06 - Audio clip===
*[https://web.archive.org/web/20191106204314/https://xkcd.com/ 2019-11-06].
**[[2224: Software Updates]] was still up when the header changed, but the first archive version was first from after the next comic came out [[2225: Voting Referendum]].
**Still promoting the new [[How To]] book, here making the image a link to the How To book on Penguin Random House's audio book, where a audit clip read by Wil Wheaton can be sampled.
***The links below to order have now changed to those with audio books.
***The header consist of an image with text, with a "blue link", above the How To book that is being folded out from closed; to partially open; to opened up on two full pages; this takes three images. The closed book is the black book with a blue readable title, How To, and unreadable white text below this as well as below the unreadable blue author name, which are below the image. The image shows Cueball putting in a light-bulb with drones under each foot while Megan, holding a ladder, and White/Black Hat are looking up at him. The partly open book still has this cover partly visible, but unreadable, as well as come unreadable text in the open side. The open book shows two pages with lots of unreadable text and three figures (maybe one is a table). Next to the open book there is an arrow to the right pointing at an audio icon with three audio lines in front. Below the header image are the links as regular text.
**The text:
***You can click here to hear a clip from the audio version of '''''How To''''', read by Wil Wheaton.
***[https://books.apple.com/us/audiobook/how-to-absurd-scientific-advice-for-common-real-world/id1475319694 Apple], [https://www.audiobooks.com/audiobook/how-to-absurd-scientific-advice-for-common-real-world-problems/369279 Audiobooks], [https://www.audible.co.uk/pd/How-To-Audiobook/1473680360?qid=1574679523&sr=1-1&pf_rd_p=c6e316b8-14da-418d-8f91-b3cad83c5183&pf_rd_r=DX3EZ14M14CFQPP9GHJY&ref=a_search_c3_lProduct_1_1 Audible], [https://play.google.com/store/books/details/Randall_Munroe_How_To?id=LzSGDwAAQBAJ Google Play], and [https://libro.fm/audiobooks/9780525635680 Libro.fm]
**The entire image is a link to the [https://www.penguinrandomhouseaudio.com/book/576760/how-to/ How To book on Penguin Random House] page, where the audio clip can he played.
***As always it is the entire picture that is a link, and not only the blue underlined text that says click here!
*It was last on the archive on [https://web.archive.org/web/20191122044456/https://xkcd.com/ 2019-11-22] when [[2231: the Time Before And After Land]] was on the front page. But it was most likely still up when [[2232: Hotel Room Party]] came out. But then changed during the next day.

===2019-10-02 - Horse vs football team===
*[https://web.archive.org/web/20191002005854/https://xkcd.com/ 2019-10-02].
**[[2210: College Athletes]] was up when the header changed.
**Still promoting the new [[How To]] book, but seeing this is no longer close to the release day the focus has changed. This time the image seems to be from one of the How To explanations in the book.
***The links below to order are the same as the previous header.
***But new text is added after the links to promote two events with Randall in New York the two days after this header came up.
****These links disappeared after a week leaving only the picture and the link to buy the book. See below.
***The header consist of an image with Cueball riding bareback on a horse. He comes from the left holding an American football. Running towards him from the right are eight American football players with helmets with three stars on the back of the helmet. Two of the players at the back are almost hidden by players in front of them. Beneath them is a line of text that belongs to the image, the period at the end of the sentence hangs in height with the center line of the last letter E... Then below the image follows the link and promotion of the NY events, these are written in regular.
**The text:
***My new book ''How To'' is out now! You can get it here.
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target] I'll be at New York Comic Con! I'm giving [https://www.newyorkcomiccon.com/Explore/Panels/Panels-And-Screenings/#/event/how-todo-anything-with-randall-munroe-creator-of-xkcd a talk on Thursday], and on
***Friday [https://smbc-comics.com/ Zach Weinersmith] and I will be hosting [https://www.caveat.nyc/event/how-to--absurd-scientific-advice-for-common-real-world-problems-10-4-2019 an event at Caveat NYC].
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
***The link to Target still seems to go the main page rather than to [https://intl.target.com/p/how-to-by-randall-munroe-hardcover/-/A-76508342 their How To book page]... Probably a still undiscovered error on Randall's part?
*This header changed, but so slightly that the changes will only be mentioned here rather than in a new section:
**The first link was last active on [https://web.archive.org/web/20191004014438/https://xkcd.com/ 2019-10-04]
**Then the day after only the second link remained from [https://web.archive.org/web/20191005041539/https://www.xkcd.com/ 2019-10-05]. [[2211: Hours Before Departure]] came out when it changed.
***But the text of this link changed as it had been a continues text from one to the other link. Also it was not entirely on it's own line, thus not as with the first link whose text was directly connected to the line with the links to buy the book.
***The new text of that link was:
****[https://smbc-comics.com/ Zach Weinersmith] and I will be hosting [https://www.caveat.nyc/event/how-to--absurd-scientific-advice-for-common-real-world-problems-10-4-2019 an event] Friday night at Caveat NYC!
****The last link was the same, but now it only covered two words not the entire end of the sentence.
***This other link was last active on [https://web.archive.org/web/20191007042707/https://xkcd.com/ 2019-10-07].
**And then the last link was gone by [https://web.archive.org/web/20191008053609/https://xkcd.com/ 2019-10-08], when [[2212: Cell Phone Functions]] came out.
*It ended on [https://web.archive.org/web/20191105164001/https://xkcd.com/ 2019-11-05] when [[2224: Software Updates]] was up.

===2019-09-30 - Tons of fun===
*[https://web.archive.org/web/20190930234245/https://xkcd.com/ 2019-09-30].
**[[2209: Fresh Pears]] was up when the header changed.
**Still promoting the new [[How To]] book, but seeing this is no longer close to the release day the focus has changed to how much fun it was for Randall to write it and how proud he is of the result. Randall, as Cueball, is saying this in the new header image.
***The links below to order are the same, except a new has been added at the end.
***The header consist of an image with Cueball standing to the left of the book, shown as tall as he is. The book is opened up on two pages with lots of unreadable text as well as three drawings, only one of these, with a circle diagram, can clearly be seen. Cueball is speaking, and the text is above him and the book. Two words are blue with a line under as if they where a link. But as always the entire image is a link. Beneath the image is the links on where to order the book.
**The text:
***Writing my new book '''''How To''''' was tons of fun and I'm so proud of the result. It's out now-Click Here to order!
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound], [https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
***The new link to Target seems to go the main page rather than to [https://intl.target.com/p/how-to-by-randall-munroe-hardcover/-/A-76508342 their How To book page]... Probably an error on Randall's part.
*It ended on October 2nd while [[2210: College Athletes]] where up. But there is no archived versions from the 1st of October and the one from the 2nd is with the next version. But the editor of this was making changes the the explanation of College Athletes before the next header change came along.

===2019-09-11 - How To available===
*[https://web.archive.org/web/20190911053115/https://xkcd.com/ 2019-09-11].
**[[2200: Unreachable State]] was still up when the header changed.
**The release day part of the promotion was changed to telling that the new [[How To]] book was available. With teasers about what is in the book below the heading. On either side of the text a picture of the book is still shown. Also the links below changed, adding three new and removing one old.
***The header consist of an image with the book shown both left and right of some text. Both books have blue title and author name, and white unreadable title and white drawing of Cueball flying on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan, who is holding a ladder. Beneath the image is the links on where to order it.
***Between the two books are two sections of text above each other, the lover with smaller font.
**The text:
***How To is available now!
***Learn how to open bottles with nuclear weapons and how to be on time for meetings by altering the Earths rotation. The book also features advice from real-life experts including Chris Hadfield and Serena Williams.
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 B&N], [https://www.barnesandnoble.com/w/how-to-randall-munroe/1130494832?ean=9780525686910#/ B&N Exclusive Edition], [http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple], [https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 Audible]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**{{w|Serena Williams}} is a famous tennis player who was also featured in one of the [[:Category:Book promotion|promotion comics]] for How To: [[2190: Serena Versus the Drones]]
**{{w|Chris Hadfield}} is a Canadian retired astronaut, engineer, and former Royal Canadian Air Force fighter pilot. The first Canadian to walk in space, Hadfield has flown two Space Shuttle missions and served as commander of the International Space Station.
***The new link to audible probably needs the user to be signed up, else it will go the the front page and ask yo to sign up. But from the archive the page can be seen [https://web.archive.org/web/20190923004816/https://www.audible.com/search?advsearchKeywords=How+To+Randall+Munroe&source_code=COMA0213WS031709&SID=PRHA9A5E24CFB--9780525635680 here].
*Up till [https://web.archive.org/web/20190922143253/https://xkcd.com/ 2019-09-22] it looked like this.
**Then on [https://web.archive.org/web/20190923145251/https://xkcd.com/ 2019-09-23] and extra link was added after Audible:
***[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/23/trackingcode/PRH3D17167A3B Target].
**[[2205: Types of Approximation]] was up when this change occurred during a weekend.
*It ended on [https://web.archive.org/web/20190929223547/https://xkcd.com/ 2019-09-29] when [[2208: Drone Fishing]] was up.

===2019-09-04 - Happy Release Day - bookstore===
*[https://web.archive.org/web/20190904051509/https://xkcd.com/ 2019-09-04].
**[[2198: Throw]] was already up when the header changed slightly, as the text below Happy release day changed.
*Most of the header stayed the same as the [[#2019-09-03 - Happy Release Day - calender|day before]], but the reference to the Gregorian/Julian calender was changed.
**The header consist of an image with the book shown both left and right of some text.Both books have blue title and author name, and white unreadable title and white drawing of Cueball flowing on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan comes who is holding a ladder. Beneath the image is the link on where to order it, now the preorder has been changed to order.
***Between the two books are two sections of text above each other, the lover with smaller font and in brackets.
**The text:
***Happy How To release day!
***Available wherever books are sold.
***(Mostly bookstores, I assume but you can always try your luck at Wendy's.)
**See below for any other details.
*It ended on [https://web.archive.org/web/20190909211737/https://xkcd.com/ 2019-09-09] when [[2200: Unreachable State]] was up.

===2019-09-03 - Happy Release Day - calendar===
*[https://web.archive.org/web/20190903051503/https://xkcd.com/ 2019-09-03]
**[[2197: Game Show]] was still up when the header changed, but it was for sure to coincide with [[2198: Throw]] which came out later on the release day while it still looked like in this version.
**Randall celebrated the release day of [[How To]], coming out the day the header changed.
***The comic is also a reference to a chapter in the book on how to throw things. A very complicated interactive comic where different persons or other living things can be chosen to throw dead or living things. The trow will then be shown below with distance measured in two units, normal and special. That is if the thrower can actually manage to throw the thing.
**The header consist of an image with the book shown both left and right of some text. The two black books have red stars around them, five on the outer side of the image and 6 on the inner, the stars are mirrored around left and right book. Both books have blue title and author name, and white unreadable title and white drawing of Cueball flying on two quadcopters to put in a light-bulb in a ceiling lamp, while White/Black? Hat is watching together with Megan, who is holding a ladder. Beneath the image is the link on where to order it, now the preorder has been changed to order.
***Between the two books are two sections of text above each other, the lover with smaller font and in brackets.
**The text:
***How To Randall Munroe
***Happy How To release day!*
***(*Gregorian calendar. The Julian edition doesn't come out for 13 more days.)
***How To Randall Munroe
***Order: [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**Most of the world uses the {{w|Gregorian calendar}}, but before it was taken into use, the {{w|Julian calendar}} was in use.
***The Julian calendar does not take into account that every 100 years a leap year should be passed as in the Gregorian calendar, and thus it is at the moment 13 days behind, as it has has this many February 29th too many. Since there should actually be a leap year every 400 year, and the last of those was 2000, then it has been 13 days since 1900, and will stay like this until 2100 when it will become 14 days.
***The image is a link to the [https://xkcd.com/how-to/ How To book page] on xkcd.
**Already the next day the part of the header below happy release day about the Gregorian calender changed. See [[#2019-09-04 - Happy Release Day - bookstore|above]].

===2019-08-27 - Out in a week===
*[https://web.archive.org/web/20190827082224/https://xkcd.com/ 2019-08-27].
**[[2194: How to Send a File]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], coming out a week from this header.
***It is only three lines of text
**The text:
***My new book, How To, comes out next week!
***Read an exclusive excerpt about transmission [https://blog.xkcd.com/2019/08/26/how-to-send-a-file/ here].
***[Four links in gray blue are given with the first words in black:] Preorder ''How To'': [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**Later [https://web.archive.org/web/20190827184229/https://xkcd.com/2194/ on the same day], (and here for the next day [https://web.archive.org/web/20190828095401/https://xkcd.com/ 2019-08-27] for the front page), more text and links where added, plus the order of the text was changed.
**The later text was:
***My new book, [https://xkcd.com/how-to/ How To], comes out in a week! ([https://blog.xkcd.com/2019/08/23/book-tour-and-contest-winner/ Book tour info])
***You can preorder it now to get a copy when it's released:
***[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
***You can also read an exclusive excerpt about file transfers [https://blog.xkcd.com/2019/08/26/how-to-send-a-file/ here].
**The link to the book tour also include the winner of the [[#2019-06-25 - People with books|contest]] to get Randall to add "your" city to his book tour.
***The winner was {{w|Juneau, Alaska}}.
*It ended on the release day 2019-09-03, so this was last on the page on [https://web.archive.org/web/20190902042108/https://xkcd.com/ 2019-09-02].

===2019-08-06 - Win a sketch===
*[http://web.archive.org/web/20190806052948/https://xkcd.com/ 2019-08-06].
**[[2185: Cumulonimbus]] was up when the header changed.
***Most likely the header changed when that comic came out on 2019-08-05. But the previous header was also out during that day.
**Randall continues to promote his new book, [[How To]], now making a competition where you can win a stick figure sketch of yourself. (Although only for US residents!)
***The image shows Hairy, with a cat at his feet and Megan (or Danish?) with a samurai sword. They are standing with their backs towards each other, the cat on the left, Megan facing right with the sword towards the words.
***Below the drawing are links to places to preorder the book.
**The text:
***Want to win a sketch of yourself as a stick figure? [https://blog.xkcd.com/2019/08/05/win-an-xkcd-sketch/ Click here] to find out how!
***[Four links in gray blue are given with the first words in black:] Preorder ''How To'': [https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
****The entire picture is a [https://blog.xkcd.com/2019/08/05/win-an-xkcd-sketch/ link] to a [[Blag]] post: ''Win an xkcd sketch''
****That is even though only the click here part of the text is in blue, like a link.
****Cause as he often has written: I still haven't figured out HTML imagemaps, most recently in the [[#2019-07-09 - Drawings from How To|2019-07-09]] header.
*The header stayed like this until [https://web.archive.org/web/20190826062701/https://www.xkcd.com/ 2019-08-26] when [[2193: Well-Ordering Principle]] was up.

===2019-08-03 - First look inside===
*[http://web.archive.org/web/20190803222711/https://xkcd.com/ 2019-08-03].
**[[2184: Unpopular Opinions]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], now stating that it comes out next month.
***Set to be released on September 3rd 2019, this update was made exactly one month before.
***The image shows text to the left of three drawings of the book: First the closed book showing the black front cover with blue and white text and white drawings, then the book is partly opened, and finally it lays opened up showing two pages, with a readable heading on the right page.
***Below the drawing are links to places to preorder the book.
**The text:
***My new book comes out next month. Click here for a first look inside!
***[On the books front cover only two thins can be read:]
****How To
****Randal Munroe.
***[These two words can also partly be read on the opening book.]
***[Only the large heading can be read on the right page of the open book:]
****How to Dig a Hole.
***[These two pages also became part of a special comic relased during the weekend when this header was up: [[Disappearing Sunday Update]].]
***[The [[Disappearing_Sunday_Update#Transcript|transcript of that comic]] describes the images in the open book.]
***[Four links in gray blue are given with the first word in black:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
****The entire picture is a [https://blog.xkcd.com/2019/08/02/how-to-chapter-list-and-introduction/ link] to a [[Blag]] post: ''How To: Chapter list and introduction''.
*It stayed up like this while the special [[Disappearing Sunday Update]] came out on Sunday 2019-08-04, and was there still on Monday [ http://web.archive.org/web/20190805050812/https://www.xkcd.com/ 2019-08-05], at least during the time that the Sudan Update was still up.
**When the next comic came out late that Monday, it probably disappeared along with the Disappearing comic, but the first update with the next header is from Tuesday [http://web.archive.org/web/20190806052948/https://xkcd.com/ 2019-08-06], but the Monday comic [[2185: Cumulonimbus]] was still on the front page at that time,.

===2019-07-23 - Back to previous header===
*[http://web.archive.org/web/20190723205152/https://xkcd.com/ 2019-07-23].
**[[2179: NWS Warnings]] was up when the header changed.
*It returned to the previous header from before the ComicCon header, see [[#2019-07-10 - Adding links|2019-07-10]]
*It stayed up until [http://web.archive.org/web/20190802192259/https://xkcd.com/ 2019-08-02] while [[2184: Unpopular Opinions]] was up. The day after when it changed that comic was still up.

===2019-07-15 - ComiCon===
*[http://web.archive.org/web/20190715181016/http://xkcd.com/ 2019-07-15].
**[[2176: How Hacking Works]] was up when the header changed.
*Randall tells that he will be at ComicCon and links to his plans there.
**The text:
***Going to San Diego Comic Con this week? I'll [https://blog.xkcd.com/2019/07/15/san-diego-comic-con/ see you there]!
****The link is to a [[Blag]] post about his plans for the ComicCon
**Randall appeared in a couple of panels, and gave a talk.
**Finally he also handed out signed copies of his new [[How To]] book more than a month before official release.
***So still promoting the book, also in this header...
*It stayed up until [http://web.archive.org/web/20190722192637/https://www.xkcd.com/ 2019-07-22] the day after the ComiCon ended, while [[2178: Expiration Date High Score]] was up.
**Then it returned to the previous header from before the ComicCon announcement when [[2179: NWS Warnings]] came out.

===2019-07-10 - Adding links===
*[http://web.archive.org/web/20190710165920/https://xkcd.com/ 2019-07-10].
**[[2173: Trained a Neural Net]] was still up when the header changed slightly from that fro the day before.
**Only change was that beneath the picture, see [[#2019-07-09 - Drawings from How To|2019-07-09]], there is now a list of four links to companies where the book can be preordered.
**The extra text:
***[Four links in gray blue are given with the first word in black:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
*Note that the day after this change, [https://web.archive.org/web/20190711172451/https://xkcd.com/ 2019-07-11], a link to [[How To]] was added to the [[Design_of_xkcd.com#xkcd_links|links]] in the top left corner of xkcd.
*The header stayed like this until [http://web.archive.org/web/20190714175710/https://xkcd.com/ 2019-07-14] when [[2175: Flag Interpretation]] was up. When it changed the day after [[2176: How Hacking Works]] was up.

===2019-07-09 - Drawings from How To===
*[http://web.archive.org/web/20190709162102/https://xkcd.com/ 2019-07-09].
**[[2173: Trained a Neural Net]] was up when the header changed.
**Randall continues to promote his new book, [[How To]].
***The image shows a small picture of his book with text on either side.
***Below are what appears to be three drawings from the book. [[Ponytail]] pole vaultig with three baloons in one hand, then text, then a truck with a house behind it speeding fast up a hill then text and finally [[Cueball]] somersaulting towards an explosion.
***To the right there is a big blue button to click for preorder, with text below.
**The text:
***New book [Arrow points to book. Title can be read: How To]
***How To: Absurd Scientific Answers to Common Real-world Problems
***It's a guide to bad ways to do things...
***...And what would happen if you tried them.
***''Boom''
***Click here to preorder
***Or click anywhere. I still haven't figured out HTML imagemaps.
****The entire picture is a [https://xkcd.com/how-to/ link] to the official [[How To]] page on xkcd: https://xkcd.com/how-to/
****See [[1572: xkcd Survey]] where Randall mentions that he cannot make imagemaps.
*It stayed up like this only for a day, then an extra line of links was added the day after while the same comic was still up, see [[#2019-07-10 - Adding links|2019-07-10]].
**But the general header stayed up first for five days, and then it returned again for 10 more days after a break to announce a [[#2019-07-15 - ComiCon|ComiCon visit]].
**So a total of 16 days with this drawing.

===2019-06-25 - People with books===
*[http://web.archive.org/web/20190625190843/https://xkcd.com/ 2019-06-25].
**[[2167: Motivated Reasoning Olympics]] was up when the header changed.
**Randall continues to promote his new book, [[How To]], and his book tour.
***The image now shows 15 people standing side by side each holding a book up in front of them with unreadable titles.
***From left: [[Megan]], [[Cueball]], a man with blonde hair, [[Science Girl]], [[Blondie]], [[Hairy]], another Hairy, [[White Hat]], a kid with curly hair, [[Hairbun]], another Cueball, another Megan, a guy with a knit cap, [[Ponytail]] and [[Beret Guy]].
***Above them is a text message.
**The text:
***Want to bring me to your town for my '''''How To''''' book tour? Click to find out how to enter the challenge!
****The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.
****In the link it is explained how to enter a competition on how to bring Randall to your city.
****Make a story using only book titles and get the books used to be held up by different individuals.
****A longer sentence will improve your chances.
*****This is indeed what this header picture shows.
*The header stayed like this until [http://web.archive.org/web/20190708155517/https://xkcd.com/ 2019-07-08] when [[2172: Lunar Cycles]] was up. When it changed the day after [[2173: Trained a Neural Net]] was up.

===2019-06-15 - Adding dates===
*[http://web.archive.org/web/20190615100645/http://xkcd.com/ 2019-06-15]
**[[2163: Chernobyl]] was up when the header changed.
**Randall only made a small change to the one that had been up for four days at this time.
**The text only changed by adding a line below the first line:
***Announcing the '''''How To''''' book tour:
***[Click here for dates and tickets]
****The rest of the header is exactly the same as on [[#2019-06-11 - Book tour|2019-06-11]], except everything is a bit smaller to make room in the same place for the extra line.
****The link is not located on the blue part of the text and it was already there before this update.
****Best guess is that not many clicked through and Randall then made it obvious that there was a link.
****The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.
****Randall has previously made it clear, in [[1572: xkcd Survey]], that he knows how to make an image a link, but not how to put the link only where he says to click. But it is easier to make a place for people to click than tell them this...
*The header stayed like this until 2019-06-25, when it changed while [[2167: Motivated Reasoning Olympics]] was up. But this one was still up when that comic came out the day before [http://web.archive.org/web/20190624162740/https://xkcd.com/ 2019-06-24].

===2019-06-11 - Book tour===
*[http://web.archive.org/web/20190611031920/https://xkcd.com/ 2019-06-11]
**[[2161: An Apple a Day]] was up when the header changed.
***'''Note''' when this change happened two new links was added to the [[Design_of_xkcd.com#xkcd_links|xkcd links]] section of xkcd.
**Randall changed the header text to announce the official book tour for his newest book ''[[How To]]'' to be released 3 months later.
**The text:
***Announcing the '''''How To''''' book tour:
***[Below this header is a map of the mainland USA with 14 labeled black dots indicates the 14 cities that the book tour will take Randall to. One red dot with five red question marks above is located beneath the map to the left, indicating a 15th city to be chosen in a contest. Above the map to the right is a small picture of the book with the blue title on the black cover. Above the book is the release date and with an arrow pointing down to the book.]
***September 3rd
***How to
***Seattle
***Portland
***San Francisco
***Santa Cruz
***Los Angeles
***Salt Lake City
***Kansas City
***Ann Arbor
***Cincinnati
***Louisville
***Cambridge
***New York
***D.C.
***Raleigh
***????? (Chosen by readers)
***[The entire picture is a [https://blog.xkcd.com/2019/06/10/book-tour-announcement/ link] to the official book tour announcement posted on the [[Blag]], with all cities and dates listed with details.]
****In the link it is explained how to enter a competition on how to bring Randall to your city.
****Make a story using only book titles and get the books used to be held up by different individuals.
****Only US cities can apply.
**The header only stayed exactly like this for three days, and was still up on [http://web.archive.org/web/20190614094729/https://xkcd.com/ 2019-06-14] when [[2162: Literary Opinions]] was on the front page.
***Then it changed slightly to indicate that the picture was a link which was not clear before. See above.

===2019-05-17 - Back to previous header===
*[http://web.archive.org/web/20190517103928/https://xkcd.com/ 2019-05-17]:
**[[2150: XKeyboarCD]] was still up when the header changed.
*It changed back to the exact same heading as before the one with Google reader here below.
**See [[#2019-02-06 - How to book|2019-02-06]] below for all details.
**It stayed up for more than three weeks and was still up on [http://web.archive.org/web/20190610055519/https://www.xkcd.com/ 2019-06-10], while [[2160: Ken Burns Theory]] was still up on the day the next comic [[2161: An Apple a Day]] was to be released (where the new header could be found at least the next day, but maybe from the release of that comic?). Then it changed to announce the book tour for his new book.

===2019-04-23 - Google Reader===
*[http://web.archive.org/web/20190423155458/https://xkcd.com/ 2019-04-23]:
**[[2140: Reinvent the Wheel]] came out when it changed, ending a more than two and half month long [[#2019-02-06 - How to book|promotion]] of Randall's new book [[How To]].
**Randall changed the header text to ask if the reader still mourned the loss of {{w|Google Reader}} which closed on 2013-07-01, almost 6 years before this comic..
***He offers the possibility to sign up to receive the newest comic by e-mail.
**The comic may have relation to this, as some where using Google reader for different purposes when they closed it, without any chance of [https://www.google.com/reader/about/ getting your data out].
***The comic "Reinvent the Wheel" mentions that using external dependencies carry risks, such as Google closing down a feature. given the fact that the comic came out as the header changed it is probably not a coincidence.
**The text:
***Still mourning the demise of Google Reader? You can sign up to get new comics delivered by email [https://xkcd.com/newsletter/ here].
**The link is to https://xkcd.com/newsletter, where it is possible to submit your e-mail address and press a subscribe button.
***the following text is written above it:
***To receive the comic and news postings in your inbox, subscribe here.
**It stayed up for more than three weeks and was still up on [http://web.archive.org/web/20190516100403/https://xkcd.com/ 2019-05-16], when [[2150: XKeyboarCD]] was up. Then it changed back to the promotion of his new book.

===2019-02-06 - How to book===
*[http://web.archive.org/web/20190206060904/https://xkcd.com/ 2019-02-06]:
**[[2107: Launch Risk]] was up at the time when it changed, having been up since Monday the 4th of February.
***Here it can be seen being on the front of xkcd on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05], without the new text. This was also the last time the standard header text was used in several months.
***[[2108: Carbonated Beverage Language Map]] came up later on the day the header changed.
**Randall changed the header text to promote his newest book ''[[How To]]'' to be released 7 months later.
***He added an image of the book with large text next to it regarding the release and links on how to preorder it.
***There was no direct relation to the comics released at the time, except of course that he kind of launched his new book with all the risk it involves, while having a comic called launch risk up. It was though a very different and more real type of launch risk (of a human carrying space rocket) in the comic.
**The text:
***[The book is shown to the left as a black rectangle with large blue text and smaller gray text. On the book cover, in white drawings, are seen Megan with a ladder and either Black or White Hat (hard to say on black background). Both are looking up on Cueball who is floating in the air with a quadcopter beneath either leg, trying to plug in an electric light bulb in a naked lamp hanging down near him. It seems he has already removed the broken light bulb, as he has one in both hands. And now he tries to put in the new one. He could have let Megan use the ladder...]
***[The header in blue above it all:] How To.
***[Sub header in gray to the left of Cueball:] Absurd Scientific Answers to Common Real-world Problems
***[Author name in blue below the drawing:] Randall Munroe
***[Sub header to this below in gray:] Creator of xkcd
***[Sub header to this below in gray:] Author of what if? and Thing Explainer
***[Next to this book image are the following text:]
***[Large heading:] HOW TO
***[Normal size sub header:] Absurd Scientific Answers to Common Real-world Problems
***[In smaller gray font below:] Available September 3, 2019.
***[Four links in gray blue are given with the first word still in gray:] Preorder:[https://www.amazon.com/How-Absurd-Scientific-Real-World-Problems/dp/0525537090/ Amazon],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/2/trackingcode/PRH5522E62429 Barnes & Noble],[http://links.penguinrandomhouse.com/type/affiliate/isbn/9780525537090/siteID/8001/retailerid/6/trackingcode/penguinrandom IndieBound],[https://itunes.apple.com/us/book/how-to/id1451461524?mt=11 Apple Books]
**It stayed up for more than two and a half month and was still up on [http://web.archive.org/web/20190422030324/https://xkcd.com/ 2019-04-22], when [[2139: Email Settings]] was up. Then it finally changed to a new header without going back to the standard.

===2018-11-07 - Back to standard text===
*[http://web.archive.org/web/20181107144453/https://www.xkcd.com/ 2018-11-07]
**The text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**It stayed like this until [[2107: Launch Risk]] was up on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05], so two days less than three months.
***After this it did not return to the standard text for almost three years, but just short of a month before the third year without it, it returned on [[#2022-01-08 - Back to standard text|2022-01-08]].

===2018-11-06 - Election Day===
*[http://web.archive.org/web/20181106122850/https://xkcd.com/ 2018-11-06]:
**[[2068: Election Night]] (on election day the day after this comic was released).
***It added a larger comic above the two links from the previous header. Those links of the previous header text was still up the day before [http://web.archive.org/web/20181105105855/https://xkcd.com/ 2018-11-05], when [[2067: Challengers]] was still up.
**Randall changed the xkcd header once more to try to make more people vote, and in this case help others to vote.
***Once again directly related to the new comic about election night.
**The text:
***[A line of altering blue and red stars, blue first and last of two rows of nine starts around of the heading:]
***Election Day!
***[Below Black Hat and Ponytail to the left and Megan to the right of Cueball is checking their smart phones. Cueball is addressing the reader:]
***Cueball: The biggest thing you can do th help is to check in with friends and family and make sure they know when and where they're voting.
***[Below these four characters there is the following text with two arrows pointing left and right. Both are turning up to text/links on either side of the four:]
***Use these links to answer questions
***[To the left:] Where and how to vote: [https://www.vote.org/ Vote-org]
***[To the right:] What's on your ballot: [https://www.ballotready.org/ BallotReady.org]
***[Below was the two links from the previous header:]
***Find out where to vote: [https://www.vote.org/ vote.org].
***See what's on your ballot: [https://www.ballotready.org/ BallotReady.org]
**It was only up one day and thus on ended the day after [http://web.archive.org/web/20181107144453/https://www.xkcd.com/ 2018-11-07] when the next comic [[2069: Wishlist]] came out.
***The text then returned to the standard xkcd header: xkcd updates every Monday, Wednesday, and Friday.
****It stayed like this until [[2107: Launch Risk]] was up on [http://web.archive.org/web/20190205050302/https://xkcd.com/ 2019-02-05].

===2018-11-02 - Where to vote===
*[http://web.archive.org/web/20181103021059/https://xkcd.com/ 2018-11-02]:
**[[2067: Challengers]] (on the Friday, it was released).
***It added another link to the previous header text. That text was still up the day before on Thursday [http://web.archive.org/web/20181102015102/https://xkcd.com/ 2018-11-01].
***That was while comic [[2066: Ballot Selfies]] was still up.
**Randall changed the xkcd header to let people know who is on their voting ballot, and as before there is also a link on how to register for voting.
***This is also directly related to the new comic that came out that day, about helping people to decide who to vote for, i.e. who is on their ballot.
**The text:
***Find out where to vote: [https://www.vote.org/ vote.org].
***See what's on your ballot: [https://www.ballotready.org/ BallotReady.org]
**This was done at this moment because the {{w|United States midterm election}} was held on {{w|United States elections, 2018|Tuesday, November 6, 2018}}, four days after the release of this comic.
**It was still up the day before the election day, [http://web.archive.org/web/20181105105855/https://xkcd.com/ 2018-11-05], and then it changed with the next comic.

===2018-10-22 - Register for voting===
*[http://web.archive.org/web/20181022120935/https://xkcd.com/ 2018-10-22]:
**[[2061: Tectonics Game]] (on a Monday, the 3rd day after release of this Friday comic)
***The standard text was still up Sunday [http://web.archive.org/web/20181021141446/https://xkcd.com/ 2018-10-21].
***The comic [[2062: Barnard's Star]] was released later that day.
**Randall changed the xkcd header to try to get people to register for voting.
**The text:
***Check your registration and find your polling place at [https://www.vote.org/ vote.org].
**This was done at this moment because the {{w|United States midterm election}} was held on {{w|United States elections, 2018|Tuesday, November 6, 2018}}, about two weeks after the release of this comic.
***It is generally believed that many of those not voting would have chosen democrats on election day, and thus Randall has an interest in getting as many as possible to register, see [[1756: I'm With Her]] (apart from the fact that he also most likely thinks that it is important to use the right to vote).
**It ended on [http://web.archive.org/web/20181103021059/https://xkcd.com/ 2018-11-02], when [[2067: Challengers]] came out.
***It was still there while [[2066: Ballot Selfies]] was still up the day before on [http://web.archive.org/web/20181102015102/https://xkcd.com/ 2018-11-01].

===2018-09-13 - NY votes today===
*[http://web.archive.org/web/20180913133544/https://xkcd.com/ 2018-09-13]
**[[2045: Social Media Announcement]] (the day after the release of the comic.)
***It was not up when the comic was released on [http://web.archive.org/web/20180912131437/https://xkcd.com/ 2018-09-12].
**It was a short lived reminder that NY votes today below the usual standard text.
**The text:
***xkcd updates every Monday, Wednesday, and Friday.
***NY votes today! Find your polling place [https://voterlookup.elections.ny.gov/ here]. (Zephyr Teachout for AG!)
**It ended with [[2046: Trum-]], the very next comic, on [http://web.archive.org/web/20180914175605/https://xkcd.com/ 2018-09-14], returning to the standard text.

===2017-11-26 - Christmas gifts===
*[http://web.archive.org/web/20171126130857/http://xkcd.com/ 2017-11-26]
**[[1920: Emoji Sports]] had been up two days [http://web.archive.org/web/20171125125648/https://xkcd.com/ 2017-11-25] before the message changed from the normal version. But it changed the day before the next comic came up.
***It was changed to a commercial for Christmas shopping with a code for getting 5$ of the price with a codes for different online shops.
**The text:
***To anyone looking for Christmas gifts: Until Monday you can get $5 off
***[https://www.amazon.com/What-International-Scientific-Hypothetical-Questions/dp/0544456866 What If?] and [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Thing Explainer] on Amazon with coupon code GIFTBOOK17.
***At Barnes & Noble, until Sunday you can get 20% off [https://www.barnesandnoble.com/w/what-if-serious-scientific-answers-to-absurd-hypothetical-questions-randall-munroe/1118864093 What If?] and [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432 Thing Explainer] using code GIVETHANKS.
**It was only up a few days and ended with [[1922: Interferometry]] on [http://web.archive.org/web/20171130150053/http://xkcd.com/ 2017-11-30] where it returned to the standard text.
***But it was still up when the comic in between [[1921: The Moon and the Great Wall]] was up on [http://web.archive.org/web/20171129140033/http://xkcd.com/ 2017-11-29].

===2017-09-22 - Visiting the UK===
*[http://web.archive.org/web/20170922232616/https://xkcd.com/ 2017-09-22]:
**[[1893: Thread]] (with its release).
***It was not up on the previous comic [[1892: USB Cables]], on the day they changed [http://web.archive.org/web/20170922025204/https://xkcd.com/ 2017-09-22].
**It was an announcement that Randall would visit the UK next week.
**The text:
***I'll be visiting the UK next week! You can join me in London from September 30-October 2 (at [https://live.newscientist.com/speakers/randall-munroe New Scientist Live], [http://www.rigb.org/whats-on/events-2017/october/public-lunchtime-talk--randall-munroe The Royal Institution], and [http://www.intelligencesquared.com/events/randall-munroe-on-making-complicated-stuff-simple/ Intelligence Squared]), then from October 3-6 in [https://www.stpetersyork.org.uk/public_lectures/randall_munroe_thing_explainer York], [https://www.eventbrite.co.uk/e/thing-explaining-with-randall-munroe-tickets-37832289396 Edinburgh], [https://www.toppingbooks.co.uk/events/ely/randall-murray-thing-explainer/ Cambridge and Ely], [https://www.eventbrite.co.uk/e/randall-munroe-book-signing-thing-explainer-tickets-38041072873 Oxford], and [http://www.cheltenhamfestivals.com/literature/whats-on/2017/randall-munroe/ Cheltenham].
**Ended with [[1900: Jet Lag]] on [http://web.archive.org/web/20171010045802/https://xkcd.com/ 2017-10-10] when the text returned to normal.
***But it was still up the day before with [[1899: Ears]] on [http://web.archive.org/web/20171009040109/https://xkcd.com/ 2017-10-09].

===2017-07-31 - Thank you===
*[http://web.archive.org/web/20170731021227/https://www.xkcd.com/ 2017-07-31]:
**[[1869: Positive and Negative Reviews]] (3rd day after release of this Friday comic)
***The comic [[1870: Emoji Movie Reviews]] was released later that day.
***Megan is holding hand with Cueball and next to them is two words above each other: Thank you.
***The image is also a link.
****The link goes to [http://web.archive.org/web/20170801042453/https://www.nytimes.com/interactive/2017/07/25/us/politics/senate-votes-repeal-obamacare.html How Each Senator Voted on Obamacare Repeal Proposals], an article showing the senate votes. (here in an archived version).
**Ended with [[1872: Backup Batteries]] on [http://web.archive.org/web/20170804152509/https://xkcd.com/ 2017-08-04], but was still up when [[1871: Bun Alert]] was up on [http://web.archive.org/web/20170803124342/https://xkcd.com/ 2017-08-03].

===2017-07-25 - Vote against health care bill===
*[http://web.archive.org/web/20170725103104/https://xkcd.com/ 2017-07-25]:
**[[1867: Physics Confession]] (2nd day after release of the comic, it was not up on the first day: [http://web.archive.org/web/20170724095252/https://xkcd.com/ 2017-07-24]).
**Randall modified the xkcd header to ask readers to support voting against Donald Trump's new health care bill.
***The header was replaced with an image which is available in an archived version [https://web.archive.org/web/20170726150959im_/https://imgs.xkcd.com/notes/call-senate.png here].
***The image is also a link (and you can click anywhere on it to go the the link that is mentioned).
****The link goes to [http://web.archive.org/web/20170729003307/https://www.trumpcareten.org/daily TrumpCare Ten] (here in an archived version).
****Randall has previously made it clear, in [[1572: xkcd Survey]], that he knows how to make an image a link, but not how to put the link only where he says to click.
***Transcript of the image:
****[Megan is holding hand with Cueball next to three lines of large text, the same height as they are:]
****Please tell your senators to vote against this health care bill. It will hurt people.
****[After these three lines there is a phone number in a very large bold font with a line of text below:]
****202-224-3121
****Or click here for more info
****[Below the above is a gray line which is split in the middle with gray text, and below that four state names in white text inside black boxes:]
****Know anyone in these states? Ask them to call, too.
****Alaska Maine Nevada Ohio West Virginia
**Ended while [[1869: Positive and Negative Reviews]] was up on [http://web.archive.org/web/20170731164828/https://xkcd.com/ 2017-07-31], when it was replaced by a ''Thank you''.
***That comic came out already [http://web.archive.org/web/20170728124230/https://xkcd.com/ three days before] (Friday comic), but was still up on [http://web.archive.org/web/20170730141019/https://www.xkcd.com/ 2017-07-30]) when the message changed sometimes between Sunday 30th and Monday 31st (where [[1870: Emoji Movie Reviews]] was released).

===2017-01-21 - Update on previous===
*[http://web.archive.org/web/20170122003124/https://xkcd.com/ 2017-01-21]:
**[[1788: Barge]]
**It came up almost a month after Christmas but did not really change the sales pitch of the previous. It just removed the link image with the large red text, see previous version below.
**The text:
***There are [https://store.xkcd.com/collections/featured four new shirts] in [https://store.xkcd.com/ the xkcd store],
***along with [https://store.xkcd.com/collections/posters posters] and [https://store.xkcd.com/collections/everything lots of other stuff]!
**Ended with [[1867: Physics Confession]] on [http://web.archive.org/web/20170725103104/https://xkcd.com/ 2017-07-25].
***That comic came up [http://web.archive.org/web/20170724095252/https://xkcd.com/ the day before] the above version of the header appeared.
***So the first day after release it was still the T-shirt commercial.
***And it did not return to the standard version in between.

===2016-11-28 - Christmas sale===
*[http://web.archive.org/web/20161128153015/http://xkcd.com 2016-11-28]
**[[1765: Baby Post]]
**This came up in time for the Christmas sale of 2016.
**The text was
***There are [https://store.xkcd.com/collections/featured four new shirts] in [https://store.xkcd.com/ the xkcd store],
***along with [https://store.xkcd.com/collections/posters posters] and [https://store.xkcd.com/collections/everything lots of other stuff]!
***Above the text there was an image with two black t-shirts with white print on the chest. They were located at either end of a large red text written in the text type used in the comic. This text said New xkcd shirts.
***The entire image was a link to the [https://store.xkcd.com/ xkcd store].
**Ended with [[1788: Barge]] [http://web.archive.org/web/20170121114423/https://xkcd.com/ 2017-01-21]

===2016-04-23 - Back to standard text===
*[https://web.archive.org/web/20160423103108/http://xkcd.com/ 2016-04-23]
**When [[1671: Arcane Bullshit]] came out (probably 2016-04-22, but no earlier archived versions exist) the text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**It stayed like this for more than 7 months until [[1764: XKCDE]] was up on [https://web.archive.org/web/20161128093459/http://xkcd.com/ 2016-11-28].

===2016-04-04 - Protip on Garden===
*[https://web.archive.org/web/20160404185353/http://www.xkcd.com/#5dbfbb82-fc20-11e5-8001-42010a8e000d 2016-04-04]
**Because of the complexity of the [[Category:April fools' comics|April fools' comic]] [[1663: Garden]], Randall needed to give people some advice, hence a [[:Category:Protip|protip]] was added.
***This came in several versions, not all managed to be documented in the archive. See more in the trivia for garden regarding the [[1663:_Garden#Header_text_after_release|Header text after release]].
**The header text became a protip with the following text (the first version not documented only had the first line):
***'''Protip''': If you don't like how your garden is growing, you can click to prune it.
***You can copy the URL to share your garden. From other browsers, it will be view-only.
**When the next comic, [[1664: Mycology]], was released two days later on [https://web.archive.org/web/20160406194653/http://xkcd.com/1664/ 2016-04-06], an extra line of text was added, due to the issues caused by Garden not being on the front page {{xkcd}} but only on the numbered page {{xkcd|1663}}.
***This change was first documented on the front page the day after on [https://web.archive.org/web/20160407010635/http://xkcd.com/ 2016-04-07]
***The change was of course also on and all the other comic and thus also on the Garden comic from [https://web.archive.org/web/20160406192530/http://xkcd.com/1663/ 2016-04-06].
**Text added below the other two lines:
***Note: If you're seeing today's comic in place of your garden, change the URL from xkcd.com/#<your code> to xkcd.com/1663/#<your code>.
****This extra line was only there until next time the comic change, so last day was [https://web.archive.org/web/20160408145017/http://xkcd.com/ 2016-04-08].
**On [https://web.archive.org/web/20160408195958/http://xkcd.com/ 2016-04-08] when [[1665: City Talk Pages]] was released the extra line was removed leaving the two written first here above.
***This was also the case on the Garden comic (and all other comics) from [https://web.archive.org/web/20160408204740/http://xkcd.com:80/1663/ 2016-04-08].
**The Protip stayed in the main header text until [https://web.archive.org/web/20160422102754/http://xkcd.com/ 2016-04-22] when [[1670: Laws of Physics]] was up.
***But even though it disappeared from main header and thus from all other comic it stayed on the Garden comic, also on [https://web.archive.org/web/20160423182630/http://xkcd.com:80/1663/ 2016-04-23].
***And it has then turned out to become one of the permanent [[xkcd_Header_text#Garden|Unique header texts]].

===2016-04-04 - Back to standard text as Garden came up===
*[https://web.archive.org/web/20160404123555/http://xkcd.com/ 2016-04-04]
**For a brief period of time, when [[1663: Garden]] was finally released, the Header text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**But this lasted less than 13 hours. (Time between the previous and next archived version is 13 hours and 7 minutes).
***As people needed guidance to the new complicated comic.

===2016-04-01 - April 1st comic - technical difficulties===
*[https://web.archive.org/web/20160401204749/https://xkcd.com/ 2016-04-01]
**When Randall had problem releasing [[1663: Garden]] several [[1663:_Garden#April_Fools.27_header_text|April Fools' header text]] arrived in short succession while [[1662: Jack and Jill]] was still up.
**Each of these where simple text.
***The first from the link abve:
****The xkcd April 1st comic is currently experiencing technical difficulties.
****Please stand by!
***The next from [https://web.archive.org/web/20160402125723/http://xkcd.com:80/ 2016-04-02] at 12:57:
****The xkcd April 1st comic is currently experiencing technical difficulties.
****Status update: Please stand by.
****Status update: This is fine. Everything is fine.
****Status update: Everything is on fire.
****Status update: Searching for calendar systems in which Saturday is April 1st.
***The next from [https://web.archive.org/web/20160402175822/http://www.xkcd.com 2016-04-02] at 17:58:
****The Friday xkcd comic is currently experiencing technical difficulties
****[Editor's note: Everything is on fire] and has been delayed until Sunday night.
**It stayed like the third version until [https://web.archive.org/web/20160404054612/http://xkcd.com/ 2016-04-04] three days after the April Fools' comic was supposed to come out, so Jack and Jill was up until it changed.
*This was what was needed to stop more than 10 months of promotion of the [[Thing Explainer]] book, see below.

===2015-12-13 - Thing Explainer is available===
*[https://web.archive.org/web/20151213194534/http://xkcd.com/ 2015-12-13]
**[[1615: Red Car]] was still up when the header changed.
***The change was that the promotion for where Randall was last week where removed and left only the promotion the book [[Thing Explainer]]:
**The text:
***Thing Explainer is available at: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
**It was last up on [https://web.archive.org/web/20160401125621/http://xkcd.com/ 2016-04-01] while [[1662: Jack and Jill]] was on the front page.
***This was the last time that Thing Explainer was [[:Category:Book promotion|promoted]] in the header text.
****The first time was [[xkcd_Header_text#2015-05-14_-_New_book_Thing_Explainer|2015-05-14]], so it had been part of the header text for almost ten and a half month. That is a record!

===2015-12-05 - Thing Explainer is available and Next week===
*[https://web.archive.org/web/20151205070539/http://xkcd.com/ 2015-12-05]
**[[1612: Colds]] was up when the header changed.
***This was also at this time the [[2015-11-24 - Pages from my new book Thing Explainer|previous header texts image] was moved below the comic.
**Randall goes back to a simple promotion of the book [[Thing Explainer]] listing where to boy it.'
***But he adds a line about where he will be next week, first to a book shop on Illinois and then later in Toronto, where the host was {{w|Ryan North}} from [https://qwantz.com/ Dinosaur comics], one of the [[Design_of_xkcd.com#Comics_I_enjoy|comics Randall enjoys]].
**The text:
***Thing Explainer is available at: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
***I'll be in [https://web.archive.org/web/20151211002159/http://www.andersonsbookshop.com/event/naperville-reads-randall-munroe Naperville, IL] and [https://web.archive.org/web/20151205205714/http://www.eventbrite.ca/e/indigo-exclusive-randall-munroe-tickets-18694384407 Toronto, ON] (with [https://qwantz.com/ Ryan North]!) next week.
**It was last up on [https://web.archive.org/web/20151212133400/http://xkcd.com:80/ 2015-12-12] while [[1615: Red Car]] was on the front page.

===2015-11-24 - Pages from my new book Thing Explainer===
*[https://web.archive.org/web/20151203234149/http://xkcd.com/ 2015-12-03]
**[[1611: Baking Soda and Vinegar]] was still up when the header changed.
***This was a special one comic header text consisting of a large image with pages and excerpts from the book [[Thing Explainer]].
***The image was larger than most comics, and took away the focus of today's comic.
***So already two days after, when [[1612: Colds]] was released, the image was relegated to the being below the comic, but inside the [[Design_of_xkcd.com#Main_comic|main comic]] segment, thus not a part of the [[Design_of_xkcd.com#Bottom_segment|bottom segment]].
****But it was displayed in the header for all comics, here [https://web.archive.org/web/20151204030024/http://xkcd.com/1609/ an example] from the comic released two comics before 1611, [[1609: Food Combinations]].
****See more (and the image) [[Thing_Explainer#Promotion_at_the_xkcd_home_page|here]] on the page for Thing Explainer.
**Description of the image:
***At the top are shown four pages from the book. Two mainly blue, left and right, with white text and large images and between them two mainly white pages with blue text and smaller images. None of the text is readable, but the two blue pages pictures can be understood even in this size.
****The first page is number 2 about an animal cell: ''Tiny bags of water you’re made of''. It shows a detailed drawing of a human cell, with text at the top, and then several labels with text beneath that have arrows pointing to different parts of the cell.
****The second page is number 31 about the cockpit of an airplane: ''Stuff you touch to fly a sky boat''. It shows the inside of a cockpit with view out of the four windows, with lots of buttons in the ceiling, and blue screens and instruments at the bottom. Out the windows can be seen clouds and Cueball hanging from a balloon (a reference to [[1110: Click and Drag]]).
*****A zoom in on this page is shown beneath the four pages, see more below.
****The third page is page 27. What is on this page is a bit difficult to see, as there are no big drawings with clear meaning. It is the second page in a two page section on Data centers, with the second page focusing on the Computer: ''Computer building''. The pictures shows the data racks, to the right, and the individual computer components put into these, to the top left, with the wiring shown below to the left. Lots of text with arrows to different parts.
****The fourth page is page 23 about Trees: ''Tree''. It clearly shows the silhouette of a white tree on blue background. Several animal live on, in and beneath it. Cueball is standing on the ground. All the text are beneath labels that points to parts of the tree or the tree dwellers.
***In between the two time two pages there is a readable text, split over five lines, with two arrow at the top going from the corners of the text to the near corners of the white pages to either side. And below three arrows, with two pointing similarly as the two top arrows, but starting at the bottom of the text, and one arrow pointing straight down from the middle of the text to the large image below.
***Beneath all this is a large image which shows a zoom in on the left part of the cockpit from the second page above. The zoom is focused on the two front windows, but only the left is entirely in the picture, and the balloon hanging Cueball, cannot be seen in this part of the right window.
****At this zoom level, most of the text van be read (that is labels written on things or having arrows pointing to them). Clouds can bee seen out of both windows and in the background a rocket launch with smoke plume below the rocket is visible. The horizon line is well defines across both windows. Some of the instruments can be seen below the windows with text written on them. And some blue areas, mainly screens can be seen.
***Beneath this picture is a line with links to where the book can be ordered, like the one from the previous header text.
**The text:
***Pages from my new book, ''Thing Explainer'': Complicated stuff in simple words.
***[Labels in the cockpit]:
****Sky
****Ground (This should be below the sky. If it's above the sky, you're either having a big problem or doing something ''really'' fun.)
****Use this stuff to tell the sky boat to fly itself.
****Fly
****How fast it feels IAS 172
****Direction HDG 240
****Fall or rise
****How high 2500
****Fly
****Helpful screen
****Where the ground is
****You are: Flying
****Look here if there is a problem
***Below this image is a line of text with the first word in black and the other are four links to where to order the book:
****Order: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
***The image is a link to [https://www.amazon.com/gp/product/0544668251/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0544668251&linkCode=as2&tag=thekcs-20&linkId=S4XRZJJKSMHOWEQU Thing Explainer on Amazon].
**It was only part of the header for two days until [https://web.archive.org/web/20151204050419/http://xkcd.com/ 2015-12-04].
***It was then moved below the comics as mentioned above from [https://web.archive.org/web/20151205070539/http://xkcd.com/ 2015-12-05] when the next comic [[1612: Colds]] came out.

===2015-11-24 - Thing Explainer is out today===
*[https://web.archive.org/web/20151124201602/http://xkcd.com/ 2015-11-24]
**[[1607: Supreme Court]] was still up, but [[1608: Hoverboard]] most have come out close to the change.
***See both [https://web.archive.org/web/20151125001228/http://xkcd.com/ 2015-11-25 00:12] and [https://web.archive.org/web/20151125230753/http://xkcd.com/ 2015-11-25 23:07].
***Since this new "comic" was actually a {{w|browser game}} made to celebrate the release of Randall's new book, ''[[Thing Explainer]]'', which was released on the same day as this comic: Tuesday, November 24, 2015. The comic thus appeared on a Tuesday, replacing that week's normal Wednesday release to coincide with the release day.
***Hence it is a shame that there is no archived versions on the 24th showing Hoverboard on the front page. Even though the new version of the Header text is shown on the 24th, but on the previous comic.
**Cause all the header text is about is the release day of Thing Explainer!
***The top part is text with a line with large letters and a line below in brackets and using smaller letters. Below that there is a line dividing the text from the next part.
***Below follows the same header that was up as early as [[#2015-05-15 - Thing Explainer details|2015-05-15]] with the open book and three lines of text.
**The text:
***My new book, [http://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ Thing Explainer], is out today!
***(If you're in NYC, you can also [https://web.archive.org/web/20150925015809/http://stores.barnesandnoble.com:80/author/11170358 come see me]!)
***A picture of the open book is shown with diagrams of a human cell on the left page and suspension bridges on the right. All held in blue nuances. And arrow goes from the first word of the text to the right to the book on the left. The text is also blue except the title of the book which is in red:
****New book: Thing Explainer
****Up Goer Five-style diagrams of things (explained in the then hundred most common words)
***Below this image is a line of text with the first word in black and the other are four links to where to order the book:
****Order: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
***The image above the order line is a link to the [[Blag]] post [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ New book: Thing Explainer].
**Already the day after [https://web.archive.org/web/20151125001228/http://xkcd.com/ 2015-11-25], when [[1608: Hoverboard]] was up, an extra line (a link) was added below the above. A line was separating it from the links above:
***[http://blog.xkcd.com/2015/11/24/a-puzzle-for-the-uk/ A puzzle for UK readers]
****This was to a blag post with A puzzle for the UK because he could not go to UK in person. So this was a kind of bonus for those who could solve it. (We need an entry on that here on xkcd...)
**On [https://web.archive.org/web/20151127114432/http://xkcd.com/ 2015-11-27] is still looked like this but then when the next comic, [[1609: Food Combinations]], came out on [https://web.archive.org/web/20151128130851/http://xkcd.com/ 2015-11-28] the line about seeing him in New York was removed.
**The version with the puzzle, but without the New York line, was then up until [https://web.archive.org/web/20151201222148/http://xkcd.com/ 2015-12-01] when [[1610: Fire Ants]] was up.
**Then on [https://web.archive.org/web/20151202225254/http://www.xkcd.com/ 2015-12-02] the line with the puzzle at the bottom was changed to:
***I'm doing a [https://www.facebook.com/AndyWeirAuthor/ live Q&A;] at 2:30pm PT with The Martian author Andy Weir.
****The link is to {{w|Andy Weir}}'s Facebook page. And the Q&A can likely not be seen anymore.
****Randall has made no less than two comics about the movie {{w|The Martian (film)|The Martian}}, [[1536: The Martian]] and [[1585: Similarities]].
***It only lasted that day, and this became the last day with this header text, so it ended while [[1611: Baking Soda and Vinegar]] was up.

===2015-10-22 - World Polio Day===
*[https://web.archive.org/web/20151022200022/http://xkcd.com/ 2015-10-22]
**[[1593: Play-By-Play]] was up when the header changed.
***Randall mentions World Polio Day and the comic he drew for Bill Gates' blog, [[XKCD Marks the Spot]].
***Although he still keeps mentioning the release date for [[Thing Explainer]].
**The text:
***We've [https://slate.com/technology/2015/08/no-new-polio-in-africa-for-one-year-gates-epidemiologist-on-vaccines-and-surveillance.html almost eradicated polio]. For World Polio Day, I drew a comic
***about the eradication efforts. You can see it on [https://www.gatesnotes.com/Health/XKCD-Marks-the-Spot Bill Gates's blog].
***My [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ new book] of complex diagrams and simple words comes out Nov 24th.
****The last line is split from the Polio announcement with a line.
**Was there until [[1607: Supreme Court]] was up on [https://web.archive.org/web/20151124065108/http://xkcd.com:80/ 2015-11-24].
***That was the day that the book was released, and when the next comic [[1608: Hoverboard]] came out, it was a celebration of the book.

===2015-09-23 - Book trip and tool===
*[https://web.archive.org/web/20150923044724/http://xkcd.com/ 2015-09-23]:
**[[1580: Travel Ghost]] was up when the header changed.
***Announcing the book trip for the [[Thing Explainer]] book as well as linking to a Thing Explainer word checker tool! Two lines of text with links.
**The text:
***News: Announcing my Thing Explainer [https://blog.xkcd.com/2015/09/22/im-going-on-a-book-trip/ book trip]. Come say hi!
***Other news: Announcing the Thing Explainer [https://blog.xkcd.com/2015/09/22/a-thing-explainer-word-checker/ word checker] tool!
****Both links are to the [[Blag]], the first a schedule for his book trip, and the second telling about Randall's new [https://xkcd.com/simplewriter/ Simple Writer] that could help you ''Write Like Up Goer Five and Thing Explainer''.
**Was there until [[1593: Play-By-Play]] was up on [https://web.archive.org/web/20151021164208/http://xkcd.com/ 2015-10-21].

===2015-09-06 - New links===
*[https://web.archive.org/web/20150906181550/http://xkcd.com/ 2015-09-06]:
**[[1573: Cyberintelligence]] was still up when the header changed.
***The promotion of the book, [[Thing Explainer]], stayed the same with a picture above links to preorder it, but the links was reduced from four to two, the amazon link changed and a new company was added for the second link removing the other three.
***See [[#2015-05-15 - Thing Explainer details|2015-05-15]] below for all details on the image.
**The new link text:
***Preorder: [https://www.amazon.co.uk/Thing-Explainer-Randall-Munroe/dp/1473620910 Amazon.co.uk}, [https://www.waterstones.com/book/thing-explainer/9781473620919 Waterstones]
**Was there until [[1579: Tech Loops]] was up on [https://web.archive.org/web/20150919220105/http://xkcd.com/ 2015-09-22].

===2015-08-09 - Back to previous header===
*[https://web.archive.org/web/20150809230825/http://xkcd.com/ 2015-08-09]:
**[[1561: Water Phase Diagram]] was still up when the header changed.
***It changed back to the exact same heading as before the one with other news here below.
****See [[#2015-05-15 - Thing Explainer details|2015-05-15]] below for all details.
**Stayed like this until [[1573: Cyberintelligence]] was out on [https://web.archive.org/web/20150905154014/https://xkcd.com/ 2015-09-05], but the only change was that the links to preorder changed from four to only two.

===2015-06-06 - Other news===
*[https://web.archive.org/web/20150606084120/http://www.xkcd.com/ 2015-06-06]
**Changed while [[1534: Beer]] was still up.
***This was just adding some "Other news", but leaving the promotion of [[Thing Explainer]] unchanged as in the [[#2015-05-15 - Thing Explainer details|previous header]], but adding two news stories in text below the link to preorder.
**The new text:
***In other news, [https://www.youtube.com/watch?v=ygrdAvmr-MA Space Weird Thing] is delightful, and I feel surprisingly invested in [https://web.archive.org/web/20150720074919/https://twitter.com/xkcdbracket @xkcdbracket's] results.
****The link to Space Weird Thing is a YouTube video with a simple words version of {{w|David Bowie|David Bowie's}} [https://www.youtube.com/watch?v=iYYRH4apXDo Space Oddity] music video, using only the top then hundred words. The creators contributes the idea to the [[1133: Up Goer Five]] diagram which also inspired the book Thing Explainer, also promoted in this header text.
****The other link is referring to [[1529: Bracket]] released 12 days before this update, as a twitter user made a survey going through all the brackets all the way to a winner was found. Seems Randall became interested in who won. See more on the comics page.
**Was there until [[1561: Water Phase Diagram]] was up on [https://web.archive.org/web/20150807181044/http://xkcd.com/ 2015-08-07]. Then it returned back to the previous header with only the promotion of the book.

===2015-05-15 - Thing Explainer details===
*[http://web.archive.org/web/20150515060322/http://www.xkcd.com/ 2015-05-15]
**[[1525: Emojic 8 Ball]]
**This was a more detailed promotion for Randall's new book: [[Thing Explainer]] to be published in November 2015, more than half a year after the announcement, compared to the previous change which was just a line and a link.
**The text:
***A picture of the open book is shown with diagrams of a human cell on the left page and suspension bridges on the right. All held in blue nuances. And arrow goes from the first word of the text to the right to the book on the left. The text is also blue except the title of the book which is in red:
****New book: Thing Explainer
****Up Goer Five-style diagrams of things (explained in the then hundred most common words)
***Below this image is a line of text with the first word in black and the other are four links to where to preorder the book:
****Preorder: [https://www.amazon.com/Thing-Explainer-Complicated-Stuff-Simple/dp/0544668251 Amazon], [https://www.barnesandnoble.com/w/thing-explainer-randall-munroe/1121864432?ean=9780544668256#/ Barnes & Noble], [https://www.indiebound.org/book/9780544668256 Indie Bound], [https://www.hudsonbooksellers.com/thingexplainer Hudson]
***The image above the preorder line is a link to the [[Blag]] post [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ New book: Thing Explainer].
**Changed while [[1534: Beer]] was up on [https://web.archive.org/web/20150605082643/http://xkcd.com/ 2015-06-05], but only to add other information. The main promotion of the book stayed the same.

===2015-05-14 - New book Thing Explainer===
*[https://web.archive.org/web/20150514053623/http://www.xkcd.com/ 2015-05-14]
**[[1524: Dimensions]] was up.
***A single line announced the new [[Thing Explainer]] book, with link to the [[Blag]] post from the day before.
**The text:
***New book: [https://blog.xkcd.com/2015/05/13/new-book-thing-explainer/ Thing Explainer!]
*The [[:Category:Book promotion|promotion of the book]] stayed up with some changes for [[xkcd_Header_text#2015-12-13_-_Thing_Explainer_is_available|more than 10 month]] first stopping when Randall had [[xkcd_Header_text#2016-04-01_-_The_xkcd_April_1st_comic_is_currently_experiencing_technical_difficulties|problems with his April Fool's comic]] in 2016... It is a record length.
**The first came already the day after so this short announcement was only up on this day and ended with the next comic. See above.
**See more details on the promotion of the book on the Thing Explainer page [[Thing_Explainer#Promotion_at_the_xkcd_home_page|here]].

===2015-02-11 - Back to standard text===
*[https://web.archive.org/web/20150211154103/http://xkcd.com/ 2015-02-11]
**When [[1485: Friendship]] came out the text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**It stayed like this until [[1523: Microdrones]] was up on [https://web.archive.org/web/20150512184622/http://xkcd.com/ 2015-05-12], so just a day more than three months.

===2015-02-04 - Valentine cards only===
*[https://web.archive.org/web/20150204051152/http://xkcd.com/ 2015-02-04]
**[[1482: NowPlaying]] came out as it changed.
***After the last day of ordering t-shirt had passed it changed back to the picture with the Valentine cards from the previous header, but without the t-shirt picture.
***See that [[#2015-01-29 - Valentine cards and shirt|header change]], but only the first picture described.
**Ended while [[1484: Apollo Speeches]] was up on [https://web.archive.org/web/20150210005540/http://xkcd.com/ 2015-02-10].

===2015-02-02 - Last day shirt===
*[https://web.archive.org/web/20150202092804/http://xkcd.com/ 2015-02-02]
**[[1481: API]] came out as it changed.
***Just letting people know it is the last chance to order the binary t-shirt.
***There was just a line of text:
**The text was:
***Today is the last day to order the limited-run [https://web.archive.org/web/20150202092804/http://teespring.com/xkcdbinaryheart binary heart shirt]!
***The last words is link to the shirt in the shop.
**Ended before the next comic was up, but still the day after, when it was too late to order: [https://web.archive.org/web/20150203022036/http://xkcd.com/ 2015-02-03].

===2015-01-29 - Valentine cards and shirt===
*[http://web.archive.org/web/20150129183442/http://xkcd.com/ 2015-01-29]
**[[1479: Troubleshooting]] was up when it changed.
***It was to tell about both the two previous updates in the same header- Both about the collaboration to make science themed Valentine's Day cards and his new Valentine t-shirt.
***There where two pictures, with a promotion of the two products and a link to them in the shop.
***On the left was text about the cards with a small drawing to the right of the text showing the four cards.
****An ant talking to an aphids; Earth rotating about the sun but locked so one side melts; an ant with a fungus growing from it's head with a heart, and a Velociraptor skeleton where the last bit of the tail is put on by a person. The text on the cards are unreadable, but they can be seen via the link.
***The text (in three lines) was:
****Webcomic science Valentine card collaboration
****The [https://web.archive.org/web/20150127161237/http://store.xkcd.com/products/webcomic-science-valentines link to the cards] from the picture.
***The picture on the left shows binary numbers 0 and 1 in white on a black background. The middle of the three lines of those have message in red text.
***The text:
****0 1 0 1 0 Binary heart 1 1 1
****1 1 1 Valentine shirt 0 1
****0 0 0 1 [limited run] 0 0 1
****The [http://web.archive.org/web/20150125080756/http://teespring.com/xkcdbinaryheart link to the shirt] from the picture.
**Ended while [[1480: Super Bowl]] was up on [https://web.archive.org/web/20150201015913/http://xkcd.com/ 2015-02-01].

===2015-01-27 - Valentine's Day cards===
*[http://web.archive.org/web/20150127161237/http://xkcd.com/ 2015-01-27]
**[[1478: P-Values]] was up when it changed.
***It was to tell that about a collaboration to make science themed Valentine's Day cards.
***There was just two lines of text:
**The text was:
***I've teamed up with three other webcomic artists
***to make [https://web.archive.org/web/20150127161237/http://store.xkcd.com/products/webcomic-science-valentines a set of science-themed Valentine's Day cards]!
**There was a link to the cards on the store.
**Ended while [[1479: Troubleshooting]] was up [https://web.archive.org/web/20150128172147/http://xkcd.com/ 2015-01-28].

===2015-01-24 - Get shirts in store===
*[http://web.archive.org/web/20150124110707/http://xkcd.com/ 2015-01-24]
**[[1477: Star Wars]] came out as it changed.
***It was to tell about a new type of t-shirt for Valentine Day.
***There was just two lines of text:
**The text was:
***For Valentine's Day, you can get a binary heart shirt
***(from {{xkcd|99|comic #99!}}) in [http://web.archive.org/web/20150125080756/http://teespring.com/xkcdbinaryheart a limited run on TeeSpring]
**There was a link to [[99: Binary Heart]] and to the relevant t-shirt on the [https://teespring.com/ Teespring] home page.
**Ended while [[1478: P-Values]] was up [http://web.archive.org/web/20150126133139/http://xkcd.com/ 2015-01-26].

===2014-12-22 - Get shirts in store===
*[http://web.archive.org/web/20141222233233/http://xkcd.com/ 2014-12-22]
**[[1463: Altitude]] came out as it changed.
***After the Christmas sale deadline there was still merchandise in the [https://store.xkcd.com/ xkcd store].
***There was just a line of text:
**The text was:
***You can get xkcd shirts, prints, and posters in the [http://shop.xkcd.com/ store]!
**The word store was a link to the shop.
**Ended while [[1476: Ceres]] was up [http://web.archive.org/web/20150123102318/http://xkcd.com/ 2015-01-23].

===2014-12-19 - Back to previous header===
*[http://web.archive.org/web/20141219092349/http://www.xkcd.com/ 2014-12-19]:
**[[1462: Blind Trials]] came out as it changed.
*It changed back to the exact same heading as before the one with order now here below.
**See [[#2014-12-17 - Christmas deadline|2014-12-17]] below for all details.
**Ended while [[1462: Blind Trials]] was still up [http://web.archive.org/web/20141221172450/http://www.xkcd.com/ 2014-12-21].

===2014-12-18 - Order now===
*[http://web.archive.org/web/20141218090650/http://www.xkcd.com/ 2014-12-18]
**[[1461: Payloads]] was still up when it changed.
***It was to alert that the deadline for shipping before Christmas from the [https://store.xkcd.com/ xkcd store] was Friday and that it was rapidly approaching. This was a follow up on the [[#2014-12-17 - Christmas deadline|Wednesdays announcement]] the day before.
***The image was just four lines of text with several red and blue words.
**The text was:
***The xkcd store Christmas shipping deadline is Friday!
***Once it passes, there is no going back. The arrow of time drags us all
***Inexorably forward toward decay and disorder. toward the end of all things.
***Towards the empty silence of the grave. Order now!
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store], not just the blue text.
**Ended a day later while [[1461: Payloads]] was still up [http://web.archive.org/web/20141216084107/http://xkcd.com/ 2014-12-16].

===2014-12-17 - Christmas deadline===
*[http://web.archive.org/web/20141217085320/http://www.xkcd.com/ 2014-12-17]
**[[1461: Payloads]] came out as it changed.
***It was to alert that the deadline for shipping before Christmas from the [https://store.xkcd.com/ xkcd store] was Friday. This was announced Wednesday two days before the deadline.
***The image was just text with the last word in each line in red and the xkcd store blue as a link.
**The text was:
***Looking for a gift?
***xkcd store Christmas shipping deadline is Friday!
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store], not just the blue text
**Ended a day later while [[1461: Payloads]] was still up!

===2014-12-03 - Christmas shopping===
*[http://web.archive.org/web/20141203132024/http://www.xkcd.com/ 2014-12-03]
**[[1455: Trolley Problem]] came out as it changed.
***It was to announce the start of the Christmas shopping on the [https://store.xkcd.com/ xkcd store]
***Four boxes with shipping details are shown. Two green and two red, alternating from green. Between them are three text messages in two, two and three lines.
**The text was:
***xkcd store
***Christmas shopping
***I will probably not ship you a bobcat.
**The entire drawing was a link to the [https://store.xkcd.com/ xkcd store].
**The bobcat is a reference to [[325: A-Minus-Minus]].
**Ended while [[1460: SMFW]] was up [http://web.archive.org/web/20141216084107/http://xkcd.com/ 2014-12-16].

===2014-11-29 - Thanks - Emily===
*[http://web.archive.org/web/20141129211604/http://xkcd.com/ 2014-11-29]
**[[1453: fMRI]] was still up when it changed.
***It was to thanks for all the help his friend Emily with cancer got through among other his previous header text [[#2014-11-27 - Help Emily| Help Emily]].
***That only needed to be up two days before the goal was met.
**The text was:
***Thank you for helping my friend Emily.
***It means so much.
**Ended three days later while [[1454: Done]] was up [http://web.archive.org/web/20141202065133/http://xkcd.com/ 2014-12-02].

===2014-11-27 - Help Emily===
*[http://web.archive.org/web/20141127005239/http://xkcd.com/ 2014-11-27]
**[[1452: Jurassic World]] came out as it changed.
***It was to help a friend who got cancer by raising money for her.
**The text was:
***Hey all. My friend Emily—the economist who helped
***me with my {{xkcd|980|money chart}}—has been fighting cancer. She's
***having a rough time and could use some [http://web.archive.org/web/20141128183414/http://www.gofundme.com/e07dqk help]. Thank you.
**There are two links, one to the [[980: Money]] comic she helped Randall create, and one for her Go Fund Me page to raise money for her cancer cure.
***The help link above is to the archived version from that time, but the link was still active in August 2019: [https://www.gofundme.com/e07dqk Helping Emily Fight Cancer].
**Ended while [[1453: fMRI]] was up [http://web.archive.org/web/20141128070838/http://www.xkcd.com/ 2014-11-28].
***She did thus not get a permanent header as did Becky on the [[#Seven_Years|Seven Years]] comic.

===2014-10-02 - what if? bestseller===
*[http://web.archive.org/web/20141002211139/http://xkcd.com/ 2014-10-02]
**[[1428: Move Fast and Break Things]] was up when it changed from the [[#2014-09-02 - what if? book out|book is out]].
**This was a month after the [[what if|what if?]] book came out.
***It added a line of red text beneath the previous header to announce that the book was the #1 New York bestseller.
**The text was:
***My book is out!
***(#1 New York bestseller!)
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1451: Background Screens]] was up [http://web.archive.org/web/20141125234520/http://xkcd.com/ 2014-11-25].

===2014-09-04 - what if? book out===
*[http://web.archive.org/web/20140904150600/http://xkcd.com/ 2014-09-04]
**[[1416: Pixels]] was up when it changed from the [[#2014-09-02 - what if? book out today|book is out today]].
**This was two days after the [[what if|what if?]] book came out.
***It only removed to today from the previous header, that had only been up two days.
**The text was:
***My book is out!
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1428: Move Fast and Break Things]] was up [http://web.archive.org/web/20141001130827/http://xkcd.com/ 2014-09-01].

===2014-09-02 - what if? book out today===
*[http://web.archive.org/web/20140902125802/http://xkcd.com/ 2014-09-02]
**[[1415: Ballooning]] was up when it changed from the [[#2014-07-23 - what if? book tour|book tour header]].
**This was the day the [[what if|what if?]] book came out. [[Cueball]] standing to the left of the text with arms raised shouts this out.. The word Book is underlined and blue to indicate a link.
**The text was:
***My book is out today!
**The entire image was a link to the [https://whatif.xkcd.com/book/ The Book] page on the [https://whatif.xkcd.com/ what if?] page on xkcd. post.
**Ended while [[1416: Pixels]] was still [http://web.archive.org/web/20140903134518/http://xkcd.com/ 2014-09-03].

===2014-07-23 - what if? book tour===
*[http://web.archive.org/web/20140723180600/http://xkcd.com/ 2014-07-23]
**[[1398: Snake Facts]]
**This was a promotion of his book tour for the [[what if|what if?]] book made by [[Cueball]] standing to the left of the text with arms raised. Several parts of the text was underlined and blue to indicate links.
**The text was:
***I'm going on a book tour! click here for a list of stops.
***Or click anywhere-this whole image is one link because I've never gotten the hang of HTML imagemaps.
**The entire image was a link to the [[Blag]] post: [https://blog.xkcd.com/2014/07/22/what-if-book-tour/ What If book tour!].
***Later Randall commented on this lacking ability in the comic: [[1572: xkcd Survey]].
**Ended while [[1415: Ballooning]] was still up [http://web.archive.org/web/20140901113916/http://xkcd.com/ 2014-09-01].

===2014-03-13 - what if? announced===
*[http://web.archive.org/web/20140313070951/http://xkcd.com/ 2014-03-13]
**[[1341: Types of Editors]] was up.
**This was the first promotion of Randall's new [[what if|what if?]] book which is shown next to two lines of text.
**The text was:
***News:
***I'm publishing a ''what if'' book!
**The entire image was a link to the [[Blag]] post: [https://blog.xkcd.com/2014/03/12/what-if-i-wrote-a-book/ What if I wrote a book?]
**Ended while [[1397: Luke]] was up [http://web.archive.org/web/20140722142115/http://xkcd.com/ 2014-07-22].

===2014-01-09 - Back to standard text===
*[https://web.archive.org/web/20140109190927/http://www.xkcd.com/ 2014-01-09]
**When [[1314: Photos]] was still up when the text returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**It stayed until [https://web.archive.org/web/20140312070248/http://xkcd.com/ 2014-03-12] when [[1340: Unique Date]] was up, a bit more than two months.

===2013-12-21 - Deadline for Christmas shipping has passed===
*[https://web.archive.org/web/20131221043417/http://www.xkcd.com/ 2013-12-21]
**It changed when [[1306: Sigil Cycle]] came out.
**This came up when it was too close to Christmas in 2013 for shipping to arrive in time for Christmas. And Randall makes a note of this, but lets people know that they could still buy presents...
**The text was
***The deadline for guaranteed Christmas shipping has passed, but if you order something from the [http://store.xkcd.com/ xkcd store], we'll get it to you as fast as possible!
**Ended when [[1314: Photos]] was up on [https://web.archive.org/web/20140108181520/http://www.xkcd.com/ 2014-01-08].

===2013-12-06 - Empty header===
*[https://web.archive.org/web/20131206213503/http://xkcd.com/ 2013-12-06]
**It changed when [[1300: Galilean Moons]] came out.
***There just where no header text. This has not happened since. It looks really weird.
**Ended when [[1305: Undocumented Feature]] was up on [https://web.archive.org/web/20131220005306/http://xkcd.com/ 2013-12-20].

===Changes not documented yet 3===
*More changes will for sure be here between this and the one below.

====Interesting links in the Archive 3====
*Just put the link here with a date and maybe a short note:
*[https://web.archive.org/web/20131205202730/http://xkcd.com/ 2013-12-05]: Xmas sale before above
*[https://web.archive.org/web/20130315162227/http://xkcd.com:80/ 2013-03-15]: Empty follows below

===2013-03-15 - Empty header===
*[https://web.archive.org/web/20130315162227/http://xkcd.com:80/ 2013-03-15]
**It changed while [[1186: Bumblebees]] was on the front page.
***After the text saying a comic would be delayed disappeared no text replaced this.
***So the header was left empty!
**This lasted until [https://web.archive.org/web/20130318072820/http://xkcd.com/ 2013-03-18] while [[1187: Aspect Ratio]] was up.

===2013-03-13 - Comic will be delayed===
*[https://web.archive.org/web/20130313133631/http://xkcd.com/ 2013-03-13]
**It changed when [[1184: Circumference Formula]] came out, likely because the next comic was delayed.
***But there is a gap of three days before where no archived version exist, so cannot say if there where more than a few hours with this text.
**The text:
***The comic will be delayed until late morning EDT.
**Ended when [[1185: Ineffective Sorts]] was up on [https://web.archive.org/web/20130313175306/http://xkcd.com:80/ 2013-03-13].
***That was later same day as the first archived version. But could have been longer as mentioned above.

===2012-11-26 - xkcd store===
*[https://web.archive.org/web/20121126235628/http://xkcd.com/1138/ 2012-11-26]
**It changed while [[1138: Heatmap]] was up.
***Notice that the above link is not from the main page, but from {{xkcd|1138}}.
***There was a gap of five days in the archive of the main page.
***The first day that it was archived from the front page was on [https://web.archive.org/web/20121201111432/http://xkcd.com/ 2012-12-01], while [[1141: Two Years]] was up.
**The standard header text is replaced with an image that makes it seem like a rip is being torn in the white region where the text used to be. Beneath the white material that has now been ripped, some text can partly be seen. It is possible to read it.
**The text:
***xkcd store
****The image is a link to the [http://store.xkcd.com/ xkcd store] (tadaaa!)
**Ended when [[1183: Rose Petals]] was up on [https://web.archive.org/web/20130311073948/http://xkcd.com:80/1183/ 2013-03-11]
***The above link is from {{xkcd|1183}}.
***Last time the front page was archived with it was though on [https://web.archive.org/web/20130309010403/http://xkcd.com/ 2013-03-09].

===2012-10-24 - Back to standard text===
*[https://web.archive.org/web/20121024082017/http://xkcd.com:80/ 2012-10-24]
**While [[1124: Law of Drama]] was on the front the header returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**It stayed until [https://web.archive.org/web/20121126035129/http://xkcd.com:80/ 2012-11-26] when [[1138: Heatmap]] was up, a few days more than a month.

===2012-10-17 - New What-If - Lightning===
*[https://web.archive.org/web/20121017232102/http://xkcd.com/1121/ 2012-10-17]
**Probably while [[1122: Electoral Precedent]] was up.
***But the link above showing it was up on the 2012-10-17 is from the previous comics page {{xkcd|1121}} [[1121: Identity]].
***But the first version archived with this header is saved on [https://web.archive.org/web/20121018082304/http://xkcd.com/ 2012-10-18]
**Randall promotes another New What-If article.
***See the [[what if]] ''{{what if|16|Today's topic: Lightning}}''.
**The text
***New What-If article:
***[http://what-if.xkcd.com/16/ What if lightning struck while you were ...]
**This lasted until [https://web.archive.org/web/20121023023404/http://xkcd.com/1121/ 2012-10-23] when [[1124: Law of Drama]] was on the front page
***This link is though from {{xkcd|1121}}.
***The last this version was archived on the front page was the day before on [https://web.archive.org/web/20121022120008/http://xkcd.com:80/ 2012-10-22].

===2012-10-10 - New What-If - Mariana Trench Explosion===
*[https://web.archive.org/web/20121010003837/http://xkcd.com/ 2012-10-10]
**[[1118: Microsoft]] was still up at this time.
**Randall promotes another New What-If article.
***See the [[what if]] ''{{what if|15|Mariana Trench Explosion}}''.
**The text
***New What-If article:
***[http://what-if.xkcd.com/15/ What if you set off a nuclear bomb in the Mariana Trench?].
**This lasted until [https://web.archive.org/web/20121016055538/http://xkcd.com:80/ 2012-10-16] when [[1121: Identity]] was up.

===2012-10-02 - This week's What-If - Short Answer Section===
*[https://web.archive.org/web/20121002231724/http://www.xkcd.com/ 2012-10-02]
**[[1115: Sky]] was still up at this time.
**Randall promotes another New What-If article.
***See the [[what if]] ''{{what if|14|Short Answer Section}}''.
**The text
***In this week's What-If article I [https://what-if.xkcd.com/14/ answer multiple reader questions].
**This lasted until [https://web.archive.org/web/20121008112434/http://xkcd.com/ 2012-10-08] when [[1118: Microsoft]] was up.

===2012-09-26 - New What-If - Laser Pointer===
*[https://web.archive.org/web/20120926163111/http://xkcd.com/1108/ 2012-09-26]
**[[1113: Killed in Action]] was up at this time.
***The link above showing it happened on the 26th is from {{xkcd|1108}}
***The first day this version was archived on the front page was on [https://web.archive.org/web/20120928003838/http://xkcd.com:80/ 2012-09-28]
**Randall promotes another New What-If article.
***See the [[what if]] ''{{what if|13|Laser Pointer}}''.
**The text
***New What-If article:
***[http://what-if.xkcd.com/13/ If everyone aimed a laser pointer at the Moon at once, would it change color?]
**This lasted until [https://web.archive.org/web/20121001080517/http://xkcd.com/ 2012-10-01] when [[1115: Sky]] was up.

===2012-09-18 - what-if.xkcd.com - Raindrop===
*[https://web.archive.org/web/20120918143653/http://www.xkcd.com/1108/ 2012-09-18]
**[[1109: Refrigerator]] was still up at this time.
***The link above showing it happened on the 18th is from {{xkcd|1108}}
***The first day this version was archived on the front page was on [https://web.archive.org/web/20120919015232/http://xkcd.com/ 2012-09-19]
**Randall promotes another What-If article on the what-if page.
***See the [[what if]] ''{{what if|12|Raindrop}}''.
**The text
***what-if.xkcd.com: [https://what-if.xkcd.com/12/ What if all of a storm's water fell in a single raindrop?].
**This lasted until [https://web.archive.org/web/20120925090123/http://xkcd.com:80/ 2012-09-25] when [[1112: Think Logically]] was up.

===Changes not documented yet 2===
*The above is the last documented.
**There will for sure be more changes earlier than this.

====Interesting links in the Archive 2====
*Just put the link here with a date and maybe a short note:
*[https://web.archive.org/web/20120917052827/http://xkcd.com:80/ 2012-09-17]: What if Droppings ends.
*[https://web.archive.org/web/20120404111213/http://xkcd.com/1031 Uniqu leopard header]
*[https://web.archive.org/web/20120713154207/http://xkcd.com/ 2012-07-13] After US main header
*[https://web.archive.org/web/20120711123734/http://xkcd.com:80/1079/ 2012-07-11] [[1079]] page on the 11th with both headers
*[https://web.archive.org/web/20120710114846/http://xkcd.com/1078/ 2012-07-10] [[1078]] but on the 10th, so US did not alter all texts.
**New site: what-if.xkcd.com, where I abuse science to answer hypothetical questions. I'll answer a new question every Tuesday.
**Was this only up one day? No links in this.
*[https://web.archive.org/web/20120710063424/http://xkcd.com/ 2012-07-10] United Shapes
*[https://web.archive.org/web/20120709045709/http://xkcd.com:80/ 2012-07-09] United Shapes

===2012-04-09- Standard text plus store link===
*[https://web.archive.org/web/20120409190952/http://xkcd.com/1026/ 2012-04-09]
**It changed when [[1040: Lakes and Oceans]] came up.
***The above link to prove this is though from comic {{xkcd|1026}} [[1026: Compare and Contrast]] the first to be found that where archived on the 9th.
***The first archived version on the main page is from [https://web.archive.org/web/20120411053543/https://xkcd.com/ 2012-04-11] when [[1041: Whites of Their Eyes]] was up.
***There where no archived version of the front page on the 9th or 10th while Lake and Oceans was up. So it was also first on the 11th that this new text could be seen, but only when it had moved to its own page number [https://web.archive.org/web/20120411052948/http://xkcd.com/1040/ 1040].
****The change probably came because of this special comic, which may became a [https://store.xkcd.com/collections/posters/products/lakes-oceans-poster poster].
**The update was to add a promotion for the store under the standard header text.
**The text
***XKCD updates every Monday, Wednesday, and Friday.
***You can get prints, posters, and t-shirts in the [http://store.xkcd.com/ store].
**This lasted until [https://web.archive.org/web/20120709004956/http://www.xkcd.com/ 2012-07-09] when [[1078: Knights]] was up, exactly three months, so although not only the standard text, the standard text was first for three months and three days, see [[#2012-04-05 - Back to standard text|below]].

===2012-04-05 - Back to standard text===
*[https://web.archive.org/web/20120405195956/http://www.xkcd.com/1021/ 2012-04-05]
**While [[1038: Fountain]] was on the front the header returned to the standard xkcd header:
***xkcd updates every Monday, Wednesday, and Friday.
**The link above to prove the date is seen on [[1021: Business Plan]].
***The first archived version on front page is from [https://web.archive.org/web/20120406111048/http://xkcd.com/ 2012-04-06], when [[1039: RuBisCO]] was up.
***A version showing Fountain with this can be found on it's own page {{xkcd|1038}} on [https://web.archive.org/web/20120406085618/http://xkcd.com:80/1038/ 2012-04-06].
****When it was archived while on the front page it still had the previous header on [https://web.archive.org/web/20120404210927/http://xkcd.com:80/ 2012-04-05].
**It stayed up, unchanged, until [https://web.archive.org/web/20120408200414/http://xkcd.com:80/ 2012-04-08] when [[1039: RuBisCO]] was up. So only three days.
***But [[#2012-04-09- Standard text plus store link|the change]] did not remove the standard text but just added a link to the store. And this version, still with the standard text at the top stayed for three more months.

===2012-03-28 - Visiting Newport News===
*[https://web.archive.org/web/20120328103319/http://xkcd.com/ 2012-03-28]
**[[1035: Cadbury Eggs]] was on the front when it changed.
***From the end of March 2012, there is a problem with the archived versions of xkcd, so they do not load properly and do not include the comic picture.
**It was to announce a talk Randall gave at his old school.
**The text:
***I'm [https://blog.xkcd.com/2012/03/22/im-visiting-cnu-on-april-4th/ visiting] Newport News, VA next week, where I'll be speaking at CNU, my old school. If you want to come, reserve a seat [https://web.archive.org/web/20120329214411/http://www.cnu.edu/pcs/xkcd/index.asp here]!
****The first link it to a post in the [[Blag]]: [https://blog.xkcd.com/2012/03/22/im-visiting-cnu-on-april-4th/ I’m visiting CNU on April 4th].
****The other link is no longer working, but the link above goes to an archived version.
**There was a special situation with this header text. For three days it was not on the front page, as the [[:Category:April fools' comics|April fools' comic]] [[1037: Umwelt]] came out and stayed from April 1st to April 3rd on the front page.
***This comic had it's own [[#Unique header text|unique header text]] from the start, one that has [[#Umwelt|stayed like this]] since!
****So from [https://web.archive.org/web/20120401151639/http://xkcd.com:80/ 2012-04-01] to [https://web.archive.org/web/20120403223453/http://www.xkcd.com/ 2012-04-03] the front page had another header:
*****You can get posters, prints, and t-shirts in the [https://store.xkcd.com/ xkcd store].
***But all the other comics kept the Visiting header on all three days as shown here:
****[https://web.archive.org/web/20120401214214/http://xkcd.com:80/1036/ 2012-04-01] from[[1036: Reviews]].
****[https://web.archive.org/web/20120402150258/http://xkcd.com/1019 2012-04-02] from [[1019: First Post]].
****[https://web.archive.org/web/20120403164523/http://xkcd.com:80/1036/ 2012-04-03] from [[1036: Reviews]].
*****The one from the 2nd of April was hardest to find, but the most important, because that was clearly in the time period where Umwelt was up, thus definitely proving that the other pages had a different header than the front page. This is rare.
**It returned to the front page on [https://web.archive.org/web/20120404210927/http://xkcd.com:80/ 2012-04-04] and stayed up until [https://web.archive.org/web/20120405195956/http://www.xkcd.com/1021/ 2012-04-05] when [[1038: Fountain]] was up.
***The link from the 5th though is from {{xkcd|1021}} [[1021: Business Plan]], the only comic archived on the 5ht to be found.
****The previous link was the last time it was archived while on the front page.

===2012-03-12 - xkcd Holistic Browser===
*[https://web.archive.org/web/20120312185125/http://xkcd.com/ 2012-03-12]
**[[1028: Communication]] was up at the time.
***From here the archive doesn't load the page properly so it is really boring to document. This goes for both first and last day of this text.
**The text:
***New: [https://web.archive.org/web/20120318153220/http://holistic.xkcd.com/ holistic.xkcd.com], the least useful web navigation tool ever.
****The link is now dead, but the link above is to an archived version.
****On that page there is the following text:
*****The XKCD Holistic Browser
*****Because we are all one.
*****Type a web address
*****and you'll be taken to one
*****typed by someone else.
*****URL:
*****Warning: This allows strangers to direct your browser!
*****They may send you to pages containing
*****porn, viruses, or Justin Bieber fanfiction.
*****At the very least, turn on private browsing.
**During the time this header was active the comic [[1031: s/keyboard/leopard/]] came out.
***It had its own [[xkcd_Header_text#Unique_header_text|unique header text]] which thus replaced this text on the front page for two days.
***But it did not replace it on all the other pages so this was the active header text during the entire period, see more here: [[xkcd_Header_text#s.2Fkeyboard.2Fleopard.2F|s/keyboard/leopard/]]
**This lasted till [https://web.archive.org/web/20120327050311/http://xkcd.com/1033 2012-03-27] while [[1034: Share Buttons]] was up.
**But the last archived version with this on the front page was the day before [https://web.archive.org/web/20120326180811/http://xkcd.com// 2012-03-26].
***The link from 27th is from an archived version of [[1033: Formal Logic]].
*[https://web.archive.org/web/20120311135259/http://xkcd.com/ 2012-03-11] Text before. For net entry below...

===Changes not documented yet 1===
*More changes will for sure be here between this and the one below.
====Interesting links in the Archive 1====
*Just put the link here with a date and maybe a short note:

[[Category:Design of xkcd]]

2549: Edge Cake

2021-12-03T20:17:19Z

172.68.110.141: /* Explanation */

{{comic
| number = 2549
| date = December 1, 2021
| title = Edge Cake
| image = edge_cake.png
| titletext = Every time IERS adds or removes a leap second, they send me a birthday cake out of superstition.
}}

==Explanation==
{{incomplete|Created by FRINGE FRUITCAKE – Please change this comment when editing this page. Do NOT delete this tag too soon.}}

[[Megan]]—possibly an {{w|IERS}} (International Earth Rotation and Reference Systems) agent—wishes Emily, represented as [[Hairbun]], Happy Birthday. This prompts a confused [[Cueball]] to ask if her birthday was sometime last month. Emily explains that she was born over the North Pole in a plane, meaning that she was born in every timezone at once. Technically though this is false, as there are some timezones (such as {{w|Nepal Standard Time|UTC+5:45}}) that are not represented at the north pole. Except for the one hour before it's midnight at the International Date Line, the date in eastern time zones is one day ahead of western time zones, so Megan would have been born on two days at once. However, since the concept of time zones is thus irrelevant, researchers in the Arctic at or near the North Pole use {{w|Coordinated Universal Time}} as the [http://www.thoughtco.com/the-north-pole-1435098 local time standard] by convention. Thus it could have been said that [[Megan]] was born on the date that it was at that time in UTC.

Furthermore, it is extremely unlikely that she would have been born at the exact instant the plane was over the north pole, indeed, it is unlikely that the plane even traveled over the exact pole, as opposed to a few miles or even feet to either side of it. With modern positioning equipment such as GPS it should have been possible to determine which time zone the plane was in when she was born. Even in the impossibly unlikely event that she was directly above the pole at the instant of her birth, at jetliner speeds the plane was travelling about ten miles per minute, so a reasonable delay of even seconds in declaring "time of birth" would have placed the plane and her clearly in one time zone.

She also says that it was February 29th (presumably it was also February 28 or March 1 in some time zones). February 29th only happens at most once every four years in the Gregorian calendar, adding to the confusion - people born on February 29th often celebrate their non-leap-year birthdays on arbitrary days (or {{w|The_Pirates_of_Penzance#Synopsis|not at all}}). Normally {{w|Birth aboard aircraft and ships|one could simply use the time zone of the city the airplane took off from}}, but the airline company was changing ownership from one country to another at the time, so this option has apparently been ruled out. This is not terribly logical however, since contracts transferring ownership usually specify an exact time (commonly one minute before or after midnight in a specific time zone to avoid confusion on which day midnight is in) to come into effect. Regardless of which time zone(s) she was in when she was born this is an absolute time and if she was born before it she would have been born in an aircraft of the first country and if after it in an aircraft of the second country. Alternately, the time zone of the city the aircraft took off from doesn't change even if nationality of the plane changes in midair, so that should have still been an option.

The punchline is that rather than try to identify the correct birthday for Emily, the {{w|BIPM}} has decided to let her have birthdays whenever she wants. This doesn't make much sense, however. As noted above even if she was born in every time zone at once it could only have been on one of two days (February 29th, plus either February 28th or March 1st). Since it is common for people born on February 29th to celebrate on February 28th in non-leap years, it would have been trivial to pick the non-leap day present in some of the time zones (either February 28th or March 1st) and declare it [[Megan]]'s birthday.

Both the comic title and Cueball's final line are puns on "{{w|edge case}}", an engineering term referring to situations or conditions that are unusual in a way likely to cause problems unless specifically accounted for. Edge pieces are generally only important with sheet goods (brownies sheet cakes, etc), which are typically cut into pieces creating a difference between pieces originating on the edge and pieces originating from the center. Since the sides of a cake are often frosted, an edge piece has two faces covered in frosting and a corner piece has three, while a center piece only has one. Depending upon your relative preferences between the surface (often icing over marzipan) and core body of the cake (which can be fruitcake, or some variety of spongecake, etc, but not actually obvious which until the cake is cut), it being an edge-faced slice can be considered a bonus. Cueball certainly seems to appreciate this.

The title text states that the {{w|IERS}} sends Emily a cake every time they add or remove a leap second, out of superstition (perhaps Megan is delivering that cake). The International Earth Rotation and Reference Systems Service is in charge of global time standards. It occasionally adds one leap-second to {{w|Coordinated Universal Time}} to adjust for changes in the rotation speed of the Earth.

==Trivia==
Hairbun was last named "Emily" in [[788: The Carriage]]. More specifically, that version of Hairbun represented Emily Dickenson, a real, historical person who had no such issues regarding her birthday.{{Citation needed}}

==Transcript==
:[Megan is walking towards Cueball and Emily (who resembles Hairbun), holding a cake.]
:Megan: Happy birthday, Emily!
:Cueball: Wait, wasn't that last month? When's your birthday, anyways?
:Emily: It's complicated.

:[A diagram of a flight path over the North Pole, with meridian lines radiating out from the center. Emily's dialogue appears above the diagram, but she herself does not appear in this panel.]
:Emily: My mom went into labor on an arctic international flight that diverted directly over the North Pole.
:Emily: I was born in every time zone at once.

:[With Megan standing behind her, Emily holds out a plate of cake to Cueball.]
:Emily: It was also February 29th, and the airline was just changing ownership between countries.
:Emily: The International Bureau of Weights and Measures finally issued a declaration that it's my birthday whenever I want.
:Emily: Cake?
:Cueball: Nice, it's all edge pieces.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]
[[Category:Time]]
[[Category:Engineering]]
[[Category:Science]]

Retractible Rocket

2021-12-01T18:19:44Z

172.68.110.141: Redirected page to 2534: Retractable Rocket

#REDIRECT [[2534: Retractable Rocket]]

the Time Before And After Land

2021-12-01T18:19:11Z

172.68.110.141: Redirected page to 2231: The Time Before and After Land

#REDIRECT [[2231: The Time Before and After Land]]

Talk:2539: Flinch

2021-11-09T10:58:39Z

172.68.110.141:

A follow-up joke: "Psychologist: I don't trust you not to give it a push."
[[User:Who, me?|Who, me?]] ([[User talk:Who, me?|talk]]) 02:13, 9 November 2021 (UTC)

A sudden wind guest wouldn't add much momentum to a smooth, small object like a bowling ball in one swing. Even given minimal friction losses (air resistance and the chain's internal friction) I very much doubt it would speed it up enough to cause much of an impact. Also, unless Cueball has very bad luck or precognitive powers, he's unlikely to have set up the experiment perfectly in line with the next unexpected gust of wind, meaning any velocity vector change is likely to make the bowling ball miss the target scientist or engineer, not hit harder. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 04:26, 9 November 2021 (UTC)

I disagree with the explanation's contention that the way Cueball is holding the ball means the experiment is being performed incorrectly. I think it's pretty clear he's not saying it will be released from exactly where he's holding it, since it's obviously not in front of any of their faces, and it's not yet above the mark on the floor. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 07:44, 9 November 2021 (UTC)
:Ditto. Although I have in mind a way in which a (passive) string support could be arranged so that upon the outward swing it unwraps a ting little bit and returns upon a marginally lower/significantly more face-ward back swing (same K+P energy totals at all points), even starting with a taught string. Or of course an active support that moves on command, but that'd be definite cheating-with-intent as opposed to an 'accident'.
:(I also imagine Randall saw the original, if not the Youtube parody, of your US Science-Explaining-Guy doing this for real. The Youtube parody had a cartoony 'face smash' edited in as the result as a (faux-?) bite back at the scientific rationalism. If I could remember the guy's name I'd have looked for video links to potentially insert, but all I'm getting is the likes of Brian Cox doing it (successfully), on a quick and broad search.) [[Special:Contributions/172.70.91.50|172.70.91.50]] 10:05, 9 November 2021 (UTC)
: "Not hung up correctly" might also mean that the hook suddenly comes loose on the way back, in which case the ball would fly into your face, wouldn't it? --[[Special:Contributions/172.68.110.141|172.68.110.141]] 10:58, 9 November 2021 (UTC)

Talk:2539: Flinch

2021-11-09T10:57:45Z

172.68.110.141:

A follow-up joke: "Psychologist: I don't trust you not to give it a push."
[[User:Who, me?|Who, me?]] ([[User talk:Who, me?|talk]]) 02:13, 9 November 2021 (UTC)

A sudden wind guest wouldn't add much momentum to a smooth, small object like a bowling ball in one swing. Even given minimal friction losses (air resistance and the chain's internal friction) I very much doubt it would speed it up enough to cause much of an impact. Also, unless Cueball has very bad luck or precognitive powers, he's unlikely to have set up the experiment perfectly in line with the next unexpected gust of wind, meaning any velocity vector change is likely to make the bowling ball miss the target scientist or engineer, not hit harder. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 04:26, 9 November 2021 (UTC)

I disagree with the explanation's contention that the way Cueball is holding the ball means the experiment is being performed incorrectly. I think it's pretty clear he's not saying it will be released from exactly where he's holding it, since it's obviously not in front of any of their faces, and it's not yet above the mark on the floor. [[User:Esogalt|Esogalt]] ([[User talk:Esogalt|talk]]) 07:44, 9 November 2021 (UTC)
:Ditto. Although I have in mind a way in which a (passive) string support could be arranged so that upon the outward swing it unwraps a ting little bit and returns upon a marginally lower/significantly more face-ward back swing (same K+P energy totals at all points), even starting with a taught string. Or of course an active support that moves on command, but that'd be definite cheating-with-intent as opposed to an 'accident'.
: "Not hung up correctly" might also mean that the hook suddenly comes loose on the way back, in which case the ball would fly into your face, wouldn't it? --[[Special:Contributions/172.68.110.141|172.68.110.141]] 10:57, 9 November 2021 (UTC)
:(I also imagine Randall saw the original, if not the Youtube parody, of your US Science-Explaining-Guy doing this for real. The Youtube parody had a cartoony 'face smash' edited in as the result as a (faux-?) bite back at the scientific rationalism. If I could remember the guy's name I'd have looked for video links to potentially insert, but all I'm getting is the likes of Brian Cox doing it (successfully), on a quick and broad search.) [[Special:Contributions/172.70.91.50|172.70.91.50]] 10:05, 9 November 2021 (UTC)