explain xkcd - User contributions [en]

1492: Dress Color

2026-03-21T15:00:43Z

Flicky: /* Explanation */ original post no longer available

{{comic
| number = 1492
| date = February 27, 2015
| title = Dress Color
| image = dress_color.png
| titletext = This white-balance illusion hit so hard because it felt like someone had been playing through the Monty Hall scenario and opened their chosen door, only to find there was unexpectedly disagreement over whether the thing they'd revealed was a goat or a car.
}}

==Explanation==
This comic shows two drawings of a woman wearing the same dress, but with different background (and body) colors. The two drawings are split with a narrow vertical portion of an image from the web.

The comic strip refers to a {{w|the dress|dress}} whose image went viral on [https://web.archive.org/web/20150227044221/https://swiked.tumblr.com/post/112174461490/officialunitedstates-unclefather Tumblr] only hours before the strip was posted and soon showed up also on [http://www.reddit.com/r/explainlikeimfive/comments/2xaprc/eli5why_does_this_dress_appear_whitegold_to_some/ Reddit], [https://twitter.com/hashtag/thedress?src=hash Twitter], [http://www.wired.com/2015/02/science-one-agrees-color-dress/ Wired] and on [http://www.nytimes.com/2015/02/28/business/a-simple-question-about-a-dress-and-the-world-weighs-in.html The New York Times].

Due to the dress's particular color scheme and the exposure of the photo, it forms an {{w|optical illusion}} causing viewers to disagree on what color the dress actually seems to be. The xkcd strip sandwiches a cropped segment of the photographed dress between two drawings which use the colors from the image against different backgrounds, leading the eye to interpret the white balance differently, demonstrating how the dress can appear different colors depending on context and the viewer's previous experiences.

Both dresses have exactly the same colors actually:
*RGB 113, 94, 58 (orange) <div style="display:inline-block; height:1em; width:1em; background-color: #715E3A"></div>
*RGB 135, 154, 189 (blue) <div style="display:inline-block; height:1em; width:1em; background-color: #879ABD"></div>

Below is an illustration demonstrating that the "colors" of the [https://nvuvu.com/collections/sparkly-dresses/ dresses] ('''link no longer active?''') are the same by connecting them with two lines with the above-mentioned colors (all the way!) and another which has one side flipped and merged into the other:

[[File:dress.png]] [[File:dress2.png]]

Similar types of illusions can be seen at Wikipedia's {{w|Optical illusion#Color_and_brightness_constancies|optical illusion page}} and [http://www.echalk.co.uk/amusements/OpticalIllusions/colourPerception/colourPerception.html echalk].

This image has sparked surprisingly heated debate in many internet communities. A select few individuals may have prior experience with optical illusions of this ilk, but because this particular image went viral - it got heavy exposure over such a short amount of time - it reached millions of people who aren't so familiar with these sorts of mind tricks. To the uninitiated, the color of the dress seems immediately obvious; when others cannot see it their way, it can be a surreal (even uncomfortable) experience.

As an aside, the retailer Roman Originals would later [http://i0.kym-cdn.com/photos/images/newsfeed/000/921/267/de3.png confirm the dress was blue with black lace], and that a white dress with gold lace was not offered among the clothing line.

The title text refers to the game show {{w|Let's Make a Deal}}, hosted by Monty Hall, which was famous for having contestants pick among several doors which either had a real prize (for example, a car) or a joke prize (for example, a goat). [[Randall]] states that people find the dress color issue just as baffling as if upon opening the chosen door no one can agree if the item behind the door is a car or a goat. This is a reference to what has become known as the "{{w|Monty Hall problem}}:" if there are two goats and a prize behind three doors, the contestant has chosen a door, and one of the unchosen doors is opened to reveal a goat, should the contestant change his/her choice? Statistically, the answer is yes, but many people find this counterintuitive; discussion of this problem in ''Parade'' magazine touched off public outrage similar to the viral dress image.

Randall is presumably pointing out how ridiculous it is for people who don't understand the underlying science to become so adamant in defending their beliefs. A spoof of the "Monty Hall problem" previously appeared in [[1282: Monty Hall]], where [[Beret Guy]] decides to take the goat.

==Transcript==
:[Two images of a woman in a dress on each side of an image of a close up of a real dress with the same colors. On the left, she is colored blue on a dark blue background, while on the right, she is brown against a white background. Her dress is the same color in each panel - the same as the real one in between.]

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Photography]]

2969: Vice President First Names

2024-08-09T05:32:14Z

Flicky:

{{comic
| number = 2969
| date = August 7, 2024
| title = Vice President First Names
| image = vice_president_first_names_2x.png
| imagesize = 364x556px
| noexpand = true
| titletext = [Political pundit on the ScrabbleTV News channel] "After four years of defying orthographic pressure, Joe ceded the top of the ticket to Kamala, who--after considering Josh, Mark, Andy, Roy, and Pete--picked Tim."
}}

==Explanation==
{{incomplete|Created by CORNELIUS LYSANDER THROCKMORTON "BOT" BOTTINGFORD - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

Randall observes that American {{w|Vice President of the United States|Vice Presidents}} since the 80s have almost all gone by short first names. It should be noted that all of the "short" first names in this strip, with the exception of John (F. Kennedy) are diminutives (or initials) of longer names, but all represent the names which the candidates preferred and publicly used. This comic was published one day after {{w|Kamala Harris}} (who replaced Biden as presidential candidate) chose {{w|Tim Walz}} as her running mate for the {{w|2024 United States presidential election|2024 presidential election}}. Both the Republican and Democratic tickets are present for 2024, since the 2024 election had not yet concluded when this comic was made. Either party winning would match the observation.

In the comic's caption, Randall amusingly describes this as an emerging "political consensus."

While not a "political" consensus per se, the observed phenomenon is a type of consensus — reflecting a multi-decade change in US societal norms — and is not simply a random coincidence.
* There has been a national US trend toward shorter names since the 1980s and 1990s, with a rise in the popularity of baby names like Ryan, Kyle, Amy and Lisa. (The trend has continued, with even shorter names like Ava, Mia and Max becoming more common in the 2000s and 2010s.)
* This has paralleled a trend in shorter business names, with companies like Dell, Cisco and eBay before the turn of the millennium and Google, Uber and Lyft after (cf. pre-1980 businesses like AT&T, BNSF or 3M which had to convert their very long names into acronyms to adapt). Product naming also began to simplify in the late 20th century, driven by marketing strategies that favored brevity and memorability, exemplified by Apple's iconic "iMac" and "iPhone" products (again, cf. names like "Tandy 1000", "Ford F 500" or "Little Debbie's Oatmeal Creme Pies").
* All of these naming trends reflect a ''general'' societal trend toward minimalism and less formality, also seen with corporate logos, product design (Apple), clothing design (Gap), furniture design (IKEA) and web/app design.

This societal shift may explain why many politicians with given names like Albert and Richard might have preferred to go by shorter, less formal sounding, more approachable names like Al and Dick, to match the zeitgeist. James Danforth Quayle additionally used his middle name (that being another common self-naming decision; or one arising from family tradition/convenience, given that James Cline Quayle was his father), one less commonly seen than the other unabbreviated name from which "Dan" might have come.

Given that trend, it is noteworthy that Vice Presidents have generally adopted shorter names, but presidents have been less likely to do so. It's possible to create theories around this (eg, the office of President is expected to have more gravitas and formality, while the Vice President has less of an official role, and wants to be more approachable), but the size of the group is small enough that it could easily be coincidence, particularly since many of those names (such as George, Barack and Kamala) can't be easily shortened. The exception, Donald Trump (which can be shortened to Don), did not become a politician until late in life, when he was already nationally famous using his full name.

The '''title text''' amusingly suggests (1) the existence of a ScrabbleTV News channel (named after {{w|Scrabble|the word game}}) staffed with (2) political pundits who (3) report Biden's decision to end his re-election campaign as being driven by orthographic (related to the writing of words) pressure to conform to the aforementioned political consensus. Having Joe Biden as President and Kamala Harris as VP violated this pattern, but elevating Harris to the presidency and selecting a short-named running mate would restore it. In addition to Tim Walz, all of the candidates considered most likely as running mate had short first names: Josh Shapiro, Mark Kelly, Andy Beshear, Roy Cooper and Pete Buttigieg. This could also be a subtle joke about political pundits tending to give confident, inaccurate hot-takes. (Biden's decision was driven, among other things, by worsening polling, rising concerns about his age, a poor debate performance against Trump and subsequent pressure from other leading Democrats.)

This is Randall's second recent comic engaging in observational comedy about US politics and Kamala Harris, the first being [[2962: President Venn Diagram]] which was published right after she rose to the top of the Democratic ticket.

{| class="wikitable"
|+ Presidential Ticket Names
! Year !! President !! Vice-President
|-
| 2024 || Donald (John {{w|Donald Trump|Trump}}‎) Kamala (Devi {{w|Kamala Harris|Harris}}) || style="background-color:lightyellow" | '''JD''' (''James David'' {{w|JD Vance|Vance}}, né James Donald Bowman)‎ '''Tim''' (''Timothy'' {{w|Tim Walz|Walz}})
|-
| 2020 || style="background-color:lightyellow" | '''Joe''' (''Joseph'' Robinette {{w|Joe Biden|Biden}} Jr.) || Kamala (Devi Harris)
|-
| 2016 || Donald (John Trump)‎ || style="background-color:lightyellow" | '''Mike''' (''Michael'' Richard {{w|Mike Pence|Pence}})
|-
| 2012 2008 || Barack (Hussein {{w|Barack Obama|Obama}} II)‎ || style="background-color:lightyellow" | '''Joe''' (''Joseph'' Robinette Biden, Jr.)
|-
| 2004 2000 || George (Walker {{w|George W. Bush|Bush}}) || style="background-color:lightyellow" | '''Dick''' (''Richard'' Bruce {{w|Dick Cheney|Cheney}})
|-
| 1996 1992 || style="background-color:lightyellow" | '''Bill''' (''William'' Jefferson {{w|Bill Clinton|Clinton}}, né W. J. Blythe III) || style="background-color:lightyellow" | '''Al''' (''Albert'' Arnold {{w|Al Gore|Gore}} Jr.)
|-
| 1988 || George (Herbert Walker {{w|George H. W. Bush|Bush}})‎ || style="background-color:lightyellow" | '''Dan''' (James ''Danforth'' {{w|Dan Quayle|Quayle}})
|-
| 1984 1980 || Ronald (Wilson {{w|Ronald Reagan|Reagan}})‎ || George (Herbert Walker Bush)
|-
| 1976 || ‎Jimmy (''James'' Earl {{w|Jimmy Carter|Carter}} Jr.) || Walter (Frederick {{w|Walter Mondale|Mondale}})
|-style="background-color:lightgray"
| 1974 || ‎Gerald (Rudolph {{w|Gerald Ford|Ford}} Jr, né Leslie Lynch King Jr.) || Nelson (Aldrich {{w|Nelson Rockefeller|Rockefeller}})*
|-style="background-color:lightgray"
| 1973 || ‎Richard (Milhous {{w|Richard Nixon|Nixon}}) || Gerald (Rudolph Ford Jr.)*
|-
| 1972 1968 || ‎Richard (Milhous Nixon) || Spiro (Theodore {{w|Spiro Agnew|Agnew}})
|-
| 1964 || Lyndon (Baines {{w|Lyndon B. Johnson|Johnson}}) || Hubert (Horatio {{w|Hubert Humphrey|Humphrey}} Jr.)
|-style="background-color:lightgray"
| 1963 || Lyndon (Baines Johnson)† || ''vacant''
|-
| 1960 || style="background-color:lightyellow" | '''John''' (Fitzgerald {{w|John F. Kennedy|Kennedy}}) || Lyndon (Baines Johnson)
|-
| 1956 1952 || Dwight (David {{w|Dwight D. Eisenhower|Eisenhower}}, né David Dwight Eisenhower) || Richard (Milhous Nixon)
|}

:Darkened rows show transitions not made via an {{w|List of United States major party presidential tickets|electoral 'ticket'}}.
::''* Replacements made in response to political scandal''
::''† Accession to Presidency due to assassination, VP position left unfilled until next election (not shown in comic)''

==Transcript==
{{incomplete transcript|Tables are bad? Do NOT delete this tag too soon.}}

:[A table is shown in a panel. Names of "Four letters or fewer" are shown in the comic on a yellow background (bolded in the table below).]
:{| class="wikitable"
! !! President !! VP
|-
| 2024 ||? Kamala ? Donald || '''Tim ? JD ?'''
|-
| 2020 || '''Joe''' || Kamala
|-
| 2016 || Donald‎ || '''Mike'''
|-
| 2008 || Barack‎ || '''Joe'''
|-
| 2000 || George || '''Dick'''
|-
| 1992 || '''Bill''' || '''Al'''
|-
| 1988 || George || '''Dan'''
|-
| 1980 || Ronald‎ || George
|-
| 1976 || ‎Jimmy || Walter
|-
| 1974 || ‎Gerald || Nelson
|-
| 1973 || ‎Richard || Gerald
|-
| 1968 || ‎Richard || Spiro
|-
| 1964 || Lyndon || Hubert
|-
| 1960 || '''John''' || Lyndon
|-
| 1952 || Dwight || Richard
|}

:[Caption below the panel:]
:Since the 1980s, a political consensus has emerged: vice presidents should have short first names.

==Trivia: Other ways to shorten names==
Politicians can also use a more casual name by using an already less unwieldy middle name (as with {{w|Mitt Romney|Willard Mitt Romney}}, but doubly-averted in Dan Quayle's case). Even when they're not shortened to four or fewer letters, names can be made more casual in other ways (as with {{w|Bernie Sanders|Bernard 'Bernie' Sanders}}). As well, some politicians were commonly called by short nicknames even if they did not run under those names (Dwight 'Ike' Eisenhower).

Some of these may have been adult decisions, a personal choice to mark adulthood (or a change of career) by a more character-distinguishing variation, others may have been 'imposed' upon them by family, friends or peers over time and become happily accepted as the norm by the recipient without any great personal consideration.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Politics]]
[[Category:Elections]]
[[Category:Comics featuring politicians]]

Talk:2742: Island Storage

2023-02-25T12:30:33Z

Flicky:

Hey at least New Zealand made it onto this map! [[Special:Contributions/172.70.178.48|172.70.178.48]] 17:46, 24 February 2023 (UTC)

Of course the proper storage mode involves packing the continents back to Gondwada layout and then hiding them on the far side ;-) [[User:RIIW - Ponder it|RIIW - Ponder it]] ([[User talk:RIIW - Ponder it|talk]]) 18:59, 24 February 2023 (UTC)

It seems worth noting that the scale was distorted to make some islands fit. Greenland has a longitudinal height of 2671 km, but has been shrunken considerably in order to be wedged into a 1725 km gap in the Gulf of Mexico. [[User:Altay|Altay]] ([[User talk:Altay|talk]]) 19:58, 24 February 2023 (UTC)
:I thought it was the size of Africa. ---[[User:Theunlucky|Theunlucky]] ([[User talk:Theunlucky|talk]]) 20:35, 24 February 2023 (UTC)
:Maybe he started with a cursed projection that makes Greenland smaller. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 20:35, 24 February 2023 (UTC)

Seeing the ?? next to the British Isles, I think part of the islands there are the Danish islands squeezed aside to make space. (Okney Islans, Fair Isle, Shetland, Hebrides, Føroyar, etc. are probaly used to fill the gaps...) [[Special:Contributions/162.158.95.82|162.158.95.82]] 20:54, 24 February 2023 (UTC)
:Those are all pretty small. I think it's more likely Svalbard/Spitsbergen. [[Special:Contributions/172.70.131.181|172.70.131.181]] 02:09, 25 February 2023 (UTC)
::There's quite a lot of Nowegian islands, some of which are fairly large. --[[Special:Contributions/172.69.79.184|172.69.79.184]] 07:37, 25 February 2023 (UTC)

Where do we mention the typo in the title text? (Should be "Scandinavian".) --[[User:Flicky|Flicky]] ([[User talk:Flicky|talk]]) 12:30, 25 February 2023 (UTC)

2446: Spike Proteins

2021-04-07T21:39:03Z

Flicky:

{{comic
| number = 2446
| date = April 5, 2021
| title = Spike Proteins
| image = spike_proteins.png
| titletext = Ugh, it's stuck to my laptop. It must have bound to the ACER-2 receptor.
}}

==Explanation==
{{incomplete|Created by a RIBOSOME from HTmL codes. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This is another comic in the [[:Category:COVID-19|COVID-19 series]] related to the {{w|2019-20 coronavirus outbreak|2020 pandemic}}, caused by the {{w|coronavirus}} {{w|SARS-CoV-2}}.

This is also another comic about the current [[:Category:COVID-19 vaccine|vaccine against COVID-19]]. A vaccine is designed to provoke an immune response from the body of the recipient, which "trains" the immune system to attack actual viruses (or bacteria). For COVID-19, the {{w|spike protein}}, necessary for the virus to bind a receptor on human cells and invade them, is the key protein for an immune response. Almost all vaccines approved for human use pre-COVID actually contain either inactivated pathogen (e.g., flu vaccine), live but safe pathogen variants (e.g., measles), or some protein from the pathogen that the immune system can respond to (e.g., pertussis). The four COVID-19 vaccines approved in the United States or the European Union as of the date of this comic, however, are all a relatively new type of vaccine that instead cause human cells to temporarily produce spike proteins, which the immune system then "learns" to attack. The Oxford-AstraZeneca and {{w|Johnson & Johnson}}’s {{w|Janssen Vaccines|Janssen}} vaccine use a technique first approved for the July 2020 Ebola vaccine, in which a genetically modified {{w|adenovirus}} is used to deliver DNA to the nuclei of the vaccine recipients' cells, which convert the DNA to {{w|Messenger RNA}} (mRNA). The recipients' cells then use the mRNA as instructions to produce spike proteins. The {{w|Pfizer}} {{w|BioNTech}} and {{w|Moderna}} vaccines are of an even newer type: m{{w|RNA vaccine}}s, which directly inject the mRNA into the body for the cells to use, and never have to enter the cell nuclei.

[[Beret Guy]], in his [[:Category:Strange powers of Beret Guy|usual fashion]], misunderstands how reality works, then reality alters to fit his view of it.

After receiving the vaccine, as he informs [[Cueball]] and [[Megan]], he claims he will now go away to make spike proteins. For him, this literally means that he (not his cells) will build them, by unexplained means. When he returns he is carrying his constructed protein, which is ''many'' orders of magnitude larger than the normal version.{{Citation needed}} He then drops it on the desk, where a laptop is being used. Cueball part-closes his screen to try to prevent the mass from landing on it - though he's only partially successful.

When a normal living body is coerced into making a spike protein, they are microscopic particles that distribute internally around the body to provoke an immune response. Beret Guy's macroscopic version provokes an understandable response of both disgust and confusion from both Cueball and Megan, who choose to ask why it is so wet. Proteins are [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2271157/ highly hydrated molecules] where water — through the moderation of its presence and absence in specific locations — plays a central role in shaping the structure and function of the protein (although it is not clear how Beret Guy knows that the spike protein should be hydrated since this is his first try). Though, of the many questions that might have been asked, it is not an entirely unreasonable snap reaction.

Beret Guy remains typically oblivious to the fuss he causes. His enthusiastic intention, apparently, is to leave his first proud creation there as he departs to construct further examples. They will likely be no less unwelcome.

Anything damp and squidgy (as ''this'' creation seems to be) would not be welcome around a laptop, for a number of reasons, and Beret Guy seems to have made a particularly messy contact with the part of the case where most such devices are likely to have clusters of unruggedised ports/connections that may not react well to the ingress of liquids.

The title text is a pun on Acer, ACER2, and ACE2. {{w|Acer Inc.|Acer}} is a brand of computers including laptops. The {{w|Angiotensin-converting enzyme 2|ACE2 receptor}}, is an [https://theconversation.com/what-is-the-ace2-receptor-how-is-it-connected-to-coronavirus-and-why-might-it-be-key-to-treating-covid-19-the-experts-explain-136928 entry point on a cell] to which the SARS-COV-2 virus attaches during the process of entering the cell. {{w|ACER2}} is a real enzyme in humans which, although unrelated to ACE2 or SARS-COV-2, may also help bind the pun together.

==Transcript==
:[Cueball is sitting in an office chair at a desk with an open laptop in front of him. Megan stands behind him looking over his shoulder. Beret Guy is in front of the desk, walking away and looking back at the two while holding a hand to his shoulder, where he got the vaccine shot.]
:Beret Guy: Got the vaccine!
:Megan: Congrats!
:Beret Guy: Time to go make spike proteins.

:[Cueball continues to work on his laptop while Megan is looking on.]

:[In a frameless, narrow panel, Beret Guy walks back carrying a large object in his arms that looks like a spike protein. But it is about half as long as he is tall, fluffy and dripping wet, flexing slightly along its length, with the Y-shaped head pointed forwards, away from Beret Guy]
:Beret Guy: OK!
:Beret Guy: Here's my first try.

:[Beret Guy drops the spike protein onto Cueball's desk with the Y-shaped end on the desk up against the back of Cueball's laptop. The movement is shown with several lines and a sound follows when it hits the desk. The head of it takes up the entire desk area not covered by the laptop, while the tail overhangs the desk. Cueball is grabbing the lid and base of his laptop with both hands, pulling it partially closed and away from the spike protein, and Megan reflexively leans away.]
:Spike Protein: Plop

:[Beret Guy turns to leave, with an outstretched finger pointing skyward. The overhanging part of the spike protein has sagged, and it is dripping some wet material over both the floor and desk. Cueball is sitting with his hands on the partially closed laptop, Megan stands normally again.]
:Beret Guy: ''More!''
:Cueball: Ewww.
:Megan: Why is it so ''wet??''

{{comic discussion}}

[[Category:COVID-19]]
[[Category:COVID-19 vaccine]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Strange powers of Beret Guy]]

1313: Regex Golf

2019-09-23T23:20:38Z

Flicky:

{{comic
| number = 1313
| date = January 6, 2014
| title = Regex Golf
| image = regex_golf.png
| titletext = <nowiki>/bu|[rn]t|[coy]e|[mtg]a|j|iso|n[hl]|[ae]d|lev|sh|[lnd]i|[po]o|ls/ matches the last names of elected US presidents but not their opponents.</nowiki>
}}

==Explanation==
The comic talks about {{w|regular expressions}}, which are a way to specify textual patterns. Given a regular expression, one can search for the pattern it specifies inside a text string. If the pattern is found, it's said that the pattern "matches" the string; if it's not found, it's said it doesn't match.

The title of the comic and the first panel is based on "[http://regex.alf.nu/ regex golf]", which is a discipline of "{{w|code golf}}", a game in which programmers attempt to solve a given programming problem using as few characters as possible, analogous to the number of {{w|golf}} shots it takes to reach the goal. In regex golfing, the programmer is given two sets of text fragments, and he or she tries to write the shortest possible regular expression which would match all elements of one set, while at the same time not matching any element from the other set.

The regex golf challenge Megan faces consists of matching all subtitles of (then extant) ''{{w|Star Wars}}'' films, while not matching any subtitle of ''{{w|Star Trek}}'' movies. {{w|Subtitle (titling)|Subtitles}} are the secondary titles of the movies, after the ''"Star Trek: "'' or ''"Star Wars Episode N: "''. For example, in ''Star Wars Episode I: The Phantom Menace'', the subtitle is ''The Phantom Menace''. In the first panel, she created a 12-character regex solving the challenge.

Then she moved on to building a tool which would automatically build such a regex for arbitrary lists of text, which could be described as {{w|meta}}- regex golfing. But as she has lost this tool, she needs to search through her files and chooses a tool called "{{w|grep}}" to find it. This implies that she needs a regular expression that would find any code that appears to be a regex golf generator, which leads to another "meta-" layer of abstraction. At the end, Megan notes this sequence of meta-meta-... might go to infinity and Cueball quips that she now has "infinite problems" as a result of her efforts; Megan retorts that she already had "infinite problems" because she's geeky enough to run meta-versions of programs on themselves, and stubborn enough to continue on until she fails, to the exclusion of all else. This also seems to be a reference to a famous quote (see also ''[[1171: Perl Problems]]''):

<blockquote>''Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.''</blockquote>

===Regular expressions===
The first regex Megan uses is <code>/m | [tn]|b/</code>, said to match ''Star Wars'' subtitles but not ''Star Trek''.

The forward slashes <code>/</code> just mark the start and end of the regex. The <code>|</code> character means "or", so the regex matches any string that contains the patterns "<code>m </code>", "<code> [tn]</code>" or "<code>b</code>" (including the spaces). The square brackets match one of the enclosed characters, meaning that "<code> [tn]</code>" matches either "<code> t</code>" or "<code> n</code>". The regex is apparently case-insensitive, because it wouldn't work otherwise.

The Star Wars subtitles match the parts of the regex in the following way:
*"The Phantom Menace" is matched by "<code>m </code>".
*"Attack of the Clones" is matched by "<code> [tn]</code>".
*"Revenge of the Sith" is matched by "<code> [tn]</code>".
*"A New Hope" is matched by "<code> [tn]</code>".
*"The Empire Strikes Back" is matched by "<code>b</code>".
*"Return of the Jedi" is matched by "<code> [tn]</code>".

Note that if the animated film "Star Wars: The Clone Wars" were included, it would not be matched by "<code> [tn]</code>" because the T is the start of the subtitle and is not preceded by a space. None of the "Star Wars:" films titles announced since this comic ("The Force Awakens", "The Last Jedi", and "The Rise of Skywalker") match this regex.

On the other hand, none of the Star Trek subtitles contains an M followed by a space, a T or an N preceded by a space, or any B, so the regex does not match any of them. Note that in the original series all subtitles start with a "T" but it's the first character so it's not preceded by a space.

Here is the list that Megan probably used:
*Original series:
**The Motion Picture
**The Wrath of Khan
**The Search For Spock
**The Voyage Home
**The Final Frontier
**The Undiscovered Country
*The Next Generation:
**Generations
**First Contact
**Insurrection
**Nemesis
*Reboot series:
**Into Darkness

"Star Trek Beyond", which was released after this comic, would incorrectly match the regex since it is the first "Star Trek" title to contain a "b". However, since "Star Trek Into Darkness" and "Star Trek Beyond" both lack a colon in their titles, it is [[1167: Star Trek into Darkness|debatable]] whether they can truely be considered to have subtitles.

In the last panel "and beyond" Megan uses the regular expression <code>/(meta-)*regex golf/</code> to describe her problem. <code>*</code> means "zero or more" of the preceding character/group (parentheses <code>()</code> group characters). So this regex matches "regex golf", "meta-regex golf", "meta-meta-regex golf", etc. In a way this is regex golf in itself, matching all levels of meta-regex golf while not matching anything else.

In the title text, there is a long regex that is the solution of another regex golf challenge: matching the last names of all elected US presidents but not their opponents. Note that the list of opponents include some people who were previously or later became presidents, or whose last name matches that of another person who was president, so taken literally this is impossible. To make this work the list of opponents must exclude any names of presidents. The regular expression itself works in a very similar way to the Star Wars/Trek one, including several different patterns separated by <code>|</code>. Each elected president matches one pattern while each opponent matches none.

The regex does not match Donald Trump, who won over Hillary Clinton in 2016, and thus would need to be updated. The regex does match Hillary Clinton's last name, but because a person with the same last name (Bill Clinton) was president, this does not count as a mistake. There was already a losing opponent called George Clinton who ran in 1792 and 1812.

Here is a list of elected president and the patterns they match:
{| class="wikitable"
!Number
!President
!Matched expression
|-
|1
|{{w|George Washington|George Washington}}
|<code>sh</code>
|-
|2
|{{w|John Adams|John Adams}}
|<code>[ae]d</code>
|-
|3
|{{w|Thomas Jefferson|Thomas Jefferson}}
|<code>j</code>
|-
|4
|{{w|James Madison|James Madison}}
|<code>[mtg]a</code>
|-
|5
|{{w|James Monroe|James Monroe}}
|<code>[coy]e</code>
|-
|6
|{{w|John Quincy Adams|John Quincy Adams}}
|<code>[ae]d</code>
|-
|7
|{{w|Andrew Jackson|Andrew Jackson}}
|<code>j</code>
|-
|8
|{{w|Martin Van Buren|Martin Van Buren}}
|<code>bu</code>
|-
|9
|{{w|William Henry Harrison|William Henry Harrison}}
|<code>iso</code>
|-
|11
|{{w|James K. Polk|James K. Polk}}
|<code>[po]o</code>
|-
|12
|{{w|Zachary Taylor|Zachary Taylor}}
|<code>[mtg]a</code>
|-
|14
|{{w|Franklin Pierce|Franklin Pierce}}
|<code>[coy]e</code>
|-
|15
|{{w|James Buchanan|James Buchanan}}
|<code>bu</code>
|-
|16
|{{w|Abraham Lincoln|Abraham Lincoln}}
|<code>[lnd]i</code>
|-
|17
|{{w|Andrew Johnson|Andrew Johnson}}
|<code>j</code>
|-
|18
|{{w|Ulysses S. Grant|Ulysses S. Grant}}
|<code>[rn]t</code>
|-
|19
|{{w|Rutherford B. Hayes|Rutherford B. Hayes}}
|<code>[coy]e</code>
|-
|20
|{{w|James A. Garfield|James A. Garfield}}
|<code>[mtg]a</code>
|-
|22
|{{w|Grover Cleveland|Grover Cleveland}}
|<code>lev</code>
|-
|23
|{{w|Benjamin Harrison|Benjamin Harrison}}
|<code>iso</code>
|-
|24
|{{w|Grover Cleveland|Grover Cleveland}}
|<code>lev</code>
|-
|25
|{{w|William McKinley|William McKinley}}
|<code>n[hl]</code>
|-
|26
|{{w|Theodore Roosevelt|Theodore Roosevelt}}
|<code>[po]o</code>
|-
|27
|{{w|William Howard Taft|William Howard Taft}}
|<code>[mtg]a</code>
|-
|28
|{{w|Woodrow Wilson|Woodrow Wilson}}
|<code>ls</code>
|-
|29
|{{w|Warren G. Harding|Warren G. Harding}}
|<code>[lnd]i</code>
|-
|30
|{{w|Calvin Coolidge|Calvin Coolidge}}
|<code>[lnd]i</code>
|-
|31
|{{w|Herbert Hoover|Herbert Hoover}}
|<code>[po]o</code>
|-
|32
|{{w|Franklin D. Roosevelt|Franklin D. Roosevelt}}
|<code>[po]o</code>
|-
|33
|{{w|Harry S. Truman|Harry S. Truman}}
|<code>[mtg]a</code>
|-
|34
|{{w|Dwight D. Eisenhower|Dwight D. Eisenhower}}
|<code>n[hl]</code>
|-
|35
|{{w|John F. Kennedy|John F. Kennedy}}
|<code>[ae]d</code>
|-
|36
|{{w|Lyndon B. Johnson|Lyndon B. Johnson}}
|<code>j</code>
|-
|37
|{{w|Richard Nixon|Richard Nixon}}
|<code>[lnd]i</code>
|-
|39
|{{w|Jimmy Carter|Jimmy Carter}}
|<code>[rn]t</code>
|-
|40
|{{w|Ronald Reagan|Ronald Reagan}}
|<code>[mtg]a</code>
|-
|41
|{{w|George H. W. Bush|George H. W. Bush}}
|<code>bu</code>
|-
|42
|{{w|Bill Clinton|Bill Clinton}}
|<code>[rn]t</code>
|-
|43
|{{w|George W. Bush|George W. Bush}}
|<code>bu</code>
|-
|44
|{{w|Barack Obama|Barack Obama}}
|<code>[mtg]a</code>
|}

Some presidents are missing because they weren't elected but became presidents after the resignation/death of their formers.

And here is a list of how many unique last names are matched by each expression:

{| class="wikitable"
!Expression
!Match count
|-
| bu
| 3
|-
| [rn]t
| 3
|-
| [coy]e
| 3
|-
| [mtg]a
| 7
|-
| j
| 3
|-
| iso
| 1
|-
| n[hl]
| 2
|-
| [ae]d
| 2
|-
| lev
| 1
|-
| sh
| 1
|-
| [lnd]i
| 4
|-
| [po]o
| 3
|-
| ls
| 1
|}

Randall's regular expression must be modified slightly, because it also matches {{w|John C. Fremont|John C. Fremont}}, the runner-up to James Buchanan in 1856, as discussed by {{w|Peter Norvig}} at [http://nbviewer.ipython.org/url/norvig.com/ipython/xkcd1313.ipynb xkcd 1313: Regex Golf]. Note that Norvig provides a small amount of Python code which actually plays regex golf with arbitrary lists, and found a shorter solution than Randall's for the ''Star Wars'' vs ''Star Trek'' game (<code>/ t|p.*e/</code>).

==Transcript==
:Regex golf:
:[Megan is sitting at a laptop. Cueball is standing behind her.]
:Megan: You try to match one group but not the other.
:Megan: /m | [tn]|b/ matches ''Star Wars'' subtitles but not ''Star Trek''.
:Cueball: Cool.

:Meta-regex golf:
:[A close-up of Megan at her laptop.]
:Megan: So I wrote a program that plays regex golf with arbitrary lists...
:Cueball (offscreen): Uh oh...

:Meta-meta-regex golf:
:[Megan typing at her laptop.]
:Megan: ...But I lost my code, so I'm grepping for files that look like regex golf solvers.
:[Cueball facepalming.]

:...And beyond:
:[Another closeup of Megan at her laptop.]
:Megan: Really, this is all /(meta-)*regex golf/.
:Cueball: Now you have ''infinite'' problems.
:Megan: No, I had those already.

==Trivia==
*There are now at least four comics that reference regular expressions. The other three are: [[208: Regular Expressions]], [[224: Lisp]], and [[1171: Perl Problems]].
*Additionally, regular expressions are mentioned in the title text of [[1277: Ayn Random]].
*A regular expression is used in the [http://what-if.xkcd.com/75/ 75th] post of [[what if?]] to calculate the answer to that week's question.
*Also, Randall mentions [http://regex.alf.nu/ a website with a regexp golf game] he got distracted by while researching for the [http://what-if.xkcd.com/78/ 78th] post of [[what if?]] (which was published one day after this comic).

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Regex]]
[[Category:Star Trek]]

2202: Earth-Like Exoplanet

2019-09-13T20:55:29Z

Flicky:

{{comic
| number = 2202
| date = September 13, 2019
| title = Earth-Like Exoplanet
| image = earth_like_exoplanet.png
| titletext = Fire is actually a potential biosignature, since it means something is filling the atmosphere with an unstable gas like oxygen. If we find a planet covered in flames, it might be an indicator that it supports life—or used to, anyway, before the fire.
}}

==Explanation==
{{incomplete|Created by an EXOPLANET SURVIVOR. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic is a reference to the recently discovered [https://www.bbc.com/news/science-environment-49648746 exoplanet K2-18b], on which water vapor has been discovered. Water is considered a biosignature for life, meaning it's an indicator that there could be life there. However, due to its size it is unlikely to actually support life.

The comic's joke is that the exoplanet in question is actually a horrible hellscape, so it would be even less likely to support life, despite the existence of water. The planet being [https://www.spaceanswers.com/deep-space/what-is-tidal-locking/ tidally locked] indicates that the same side would face the sun year-round, so half of the planet would be in constant day, and the other half would be in constant night. [https://www.space.com/massive-stellar-flare-detected-from-distant-star.html stellar flares] are ejections of energy and plasma from a star, and it's probable that a planet being blasted with these searing hot flares wouldn't readily support life. Meteors are chunks of material that enter a planet's atmosphere, and if the planet is "blasted" by them it is likely that many of them are impacting the surface, thus becoming meteorites. As we know from [https://www.tulane.edu/~sanelson/Natural_Disasters/impacts.htm the dinosaurs], meteorites can have a negative effect on a planets habitability.

The title text mentions that fire is also a biosignature of life, and here the joke is continued, since it's unlikely anything could survive on a flaming planet.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Side view of Megan standing behind a lectern, speaking to an audience:]
:Megan: We've discovered the most earth-like exoplanet yet!
:Off-screen (at least two audience members): Yay!!

:[Frontal view of Megan behind lectern:]
:Megan: Well, it's in the habitable zone. Habitable-ish. "Habitable."
:Megan: The survivable zone.

:[Frameless panel showing frontal view of Megan behind lectern with her left hand held out palm-side up:]
:Megan: It's tidally locked. And blasted with stellar flares. And probably meteors. And bathed in acid.

:[Closeup view of Megan, now holding up a finger on her left hand:]
:Megan: But we've detected water vapor! In between all the swinging blades.
:Off-screen: I see.
:Megan: We're hoping to find biosignatures in the form of screaming.

{{comic discussion}}

[[Category:Comics featuring Megan]][[Category:Exoplanets]]

2189: Old Game Worlds

2019-08-14T19:09:38Z

Flicky:

{{comic
| number = 2189
| date = August 14, 2019
| title = Old Game Worlds
| image = old_game_worlds.png
| titletext = Ok, how many coins for a cinnamon roll?
}}

==Explanation==
{{incomplete|Created by a VERY OLD GAME CHARACTER. Do NOT delete this tag too soon.}}

[[Randall]] sits at his computer looking at a menu of games which have been ordered into three sections, New, Old and Very old games (see [[#List of games|List of games]] below). At the bottom of this list, 2nd to last, he chooses to click on ''{{w|Super Mario Bros.}}'' which then opens as shown in the next four panels.

This comic explores the difference between the real world, where artificial structures require constant upkeep and communities change with time, and the digital worlds of video games, where everything is static until the plot demands otherwise. Although ''online'' games do require server maintenance by the owners, offline games are - and always have been - perpetual existences, unchanging so long as the data is intact.

As the narration explores this incongruity, and theorizes about the idea of it not being so, the comic displays the alternative with the ubiquitous video game - ''Super Mario Bros.'' (1985) - as an example. {{w|Mario}} arrives in World 1-1 to find a {{w|Goomba}} expressing surprise that the plumber has deigned to return to the place where his '''first''' journey began. As he advances, he finds both signs of progress - a {{w|Cell site|cellphone tower}}, an {{w|Motorized scooter|e-scooter}}, a {{w|Quadcopter|drone}} - and signs of disrepair - damaged {{w|Warp (video gaming)|Warp Pipes}}, loose blocks. At World 1-Castle, he finds {{w|Toad (Nintendo)|Toad}} - usually warning him that {{w|Princess Peach|the Princess}} is being held elsewhere - informing him that the castle has been remodeled into a {{w|Panera Bread|Panera}} bakery. As shown in the previous comic, [[2188: E Scooters]] are not universally seen as a good thing. Similar, the selected modern elements, cellphone towers and (surveillance) drones, also might put a dystopian feel to the changed video game world.

The title-text abruptly switches to Mario's acceptance of the changes to World 1-1, and deciding to make the most of it by purchasing a {{w|cinnamon roll}}. "Coins" are the ubiquitous currency of the {{w|Mushroom Kingdom}} and most other locations Mario visits in the ''Mario'' series, taking the form of large nondescript golden circles, usually with a rectangular indent on the sides.

The concept of an old, dilapidated version of the world of the original Super Mario Bros. was explored by Nintendo themselves in the [https://www.ssbwiki.com/Mushroomy_Kingdom Mushroomy Kingdom] stage featured in multiple Super Smash Bros. games.

===List of games===
The first panel shows a list of games in approximately reverse chronological order of their release:
#New games:
##{{w|Subnautica}} (2014)
##[https://spookysquid.com/rsd Russian Subway Dogs] (2018)
##{{w|Kerbal Space Program}} (2015). (Has been mentioned several times in xkcd).
#Old games:
##{{w|Worms Armageddon}} (1999)
##{{w|Elasto Mania}} (2000)
##{{w|Katamari Damacy}} (2004)
##{{w|Mario Kart 64|Mario Kart}} (1997). Aka Mario Kart 64! (A [[:Category:Mario Kart|recurring]] theme).
#Very old games:
##{{w|Link's Awakening}} (1993) (aka The Legend of Zelda: Link's Awakening)
##{{w|Escape Velocity (video game)|Escape Velocity}} (1996)
##{{w|SimCity}} (1989)
##{{w|Prince of Persia}} (1989). (This game was [https://www.explainxkcd.com/wiki/images/e/e2/1608_Comparing_Prince_of_Persia_maze_with_real_level_1.png featured] in [[1608: Hoverboard]]).
##{{w|Super Mario Bros.}} (1985)
##{{w|History_of_Microsoft_Flight_Simulator#Flight_Simulator_3.0|MS Flight Simulator 3}} (1988)

The first game in the {{w|Mario Kart}} series was {{w|Super Mario Kart}} from 1992. As can be seen that Mario Kart game would be older than Link's Awakening. So it seems likely Randall was referring to {{w|Mario Kart 64}} from 1997, the first in the series to begin with Mario Kart leaving out the Super. With this in mind all the games in the two bottom sections are older than all those in the previous section. But they are not listed chronologically within the three sections.

Russian Subway Dogs is the newest game from 2018 (and at the time of this comic's release in August 2019, is the only one of the 13 games mentioned in this comic that does not currently have a Wikipedia entry).

Super Mario Bros., the game most prominently featured in the comic, is the oldest of the 13. The first version of {{w|Microsoft Flight Simulator}}, {{w|History_of_Microsoft_Flight_Simulator#Flight_Simulator_1.0|MS flight simulator 1.0}}, was from 1982, but the list this comic specifies the third version, released in 1988.

Although the games in this comic appear to be grouped by date of their release, the time span covered by these groupings is not uniform. The first three games mentioned are from 2014-2018. The next four date from between 1997-2004, and the last six from between 1985-1996. With the earliest games grouped as 1985-1996, uniform grouping could split the later games between a group released in 1997-2008 and a group of games released in 2009 or later. If grouped by decades, 1985-1995 would potentially place the Escape Velocity game in the Old Games section instead of the Very Old Games section. Although some of these games did have releases intended to run on a {{w|Personal_computer|'Personal Computer'}}, the list in this comic seems to focus on games released for {{w|Video_game_console|gaming consoles}}, with no mention of games released for {{w|First_generation_of_video_game_consoles|first}} or {{w|Second_generation_of_video_game_consoles|second}} generation {{w|List_of_home_video_game_consoles|consoles which pre-dated}} the {{w|Nintendo_Entertainment_System|Nintendo Entertainment System}} (such as {{w|Pong#Home_version|Pong}} published by Atari; {{w|Magnavox_Odyssey#cite_ref-VGHttl_2-18|Brain Wave, Haunted House, Interplanetary Voyage, & Wipeout}} for the {{w|Magnavox_Odyssey|Magnavox Odyssey}}; & {{w|Adventure_(Atari_2600)|Adventure}} for the {{w|Atari_2600|Atari 2600}}).

==Transcript==
:[A light gray drop down menu is shown with three sections split up with three grays lines split up with section titles in the same gray font. Beneath each section title is 3, 4 and 6 lines of black text. An white arrow cursor hovers over the second last option, which is thus highlighted with a dark gray background and white text.]
:New Games
:Subnautica
:Russian Subway Dogs
:Kerbal Space Program
:Old Games
:Worms Armageddon
:Elasto Mania
:Katamari Damacy
:Mario Kart
:Very Old Games
:Link's Awakening
:Escape Velocity
:SimCity
:Prince of Persia
:Super Mario Bros
:MS Flight Simulator 3

:[A colorful scene is shown from the Super Mario Bros. side-scrolling game, the first level World 1-1. Mario with red hat and trousers is standing on the brown blocks beneath the blue sky. Another character in the game, Goomba, is standing in front of some green bushes. Above them is narration text:]
:Narrator: It feels weird that you can go into old games and the whole world is still there.
:Goomba: Mario?
:Mario: It'sa me!
:Goomba: What are ''you'' doing here?

:[Mario stands between an e-scooter, a dismounted and broken Question Mark Box lying on its side and a cellphone tower. Narration continues above:]
:Narrator: Part of me expects to find that everything's changed.

:[Mario looks at a damaged green but rusty Warp Pipe and there is a quadcopter drone flying by over his head. Weeds are growing both from the pipe and from the blocks he is walking on. Narration continues above:]
:Narrator: That pipes have rusted, walls have crumbled, bad guys have moved on.

:[Mario has moved on to World 1-Castle, the castle has been replaced with a bakery. The blocks beneath his feet are now smaller and gray and above them is black background. The character Toad with the white hat with red circles is standing in front of a bakery disc with shelves of bread and cake behind it. There is a green sign on the front of the brown disk. Toad talks to Mario with white text in the black background. Above the black part of the image is more narration in a frame-less white section:]
:Narrator: That even our game worlds can't escape the passage of time.
:Toad: Thank you, Mario!
:Toad: But this is a Panera now!
:Sign: Panera

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Video games]]
[[Category:Mario Kart]]
[[Category:Drones]]

2165: Millennials

2019-06-19T18:47:40Z

Flicky:

{{comic
| number = 2165
| date = June 19, 2019
| title = Millennials
| image = millennials.png
| titletext = Ironically, I've been having these same arguments for at least a decade now. I thought we would have moved on by now, but somehow the snide complaints about millennials continue.
}}

==Explanation==
{{incomplete|Created by a MILLENIAL. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

According to [[1962: Generations|the definitive chronology of generations]], millenials are born between 1982 and 1999. Those born in 1982 reached adulthood (18 years) in 2000. As of writing of this comic (mid 2019), this is about 20 years ago. When the term became widespread around 2012, people born in 1982 were 30 years old, so the image was popularized of millenials as "college kids". The definition of the word in everyday usage seems to be expanding so that it can now includes those that were originally Gen Y, some of Gen X, as well as the gap in between them, while still including current college kids.

In this strip, [[White Hat]] expresses a sentiment of prejudice against millennials, claiming they aren’t prepared for “the real world.” This is a sentiment that sometimes can be found among those of older generations.
However, [[Cueball]] refutes this by saying that many millennials have been adults for almost 20 years, and those that had kids early on are taking them to college. This is due to another common misunderstanding, where the definition of “millennial” has changed so much, and expanded so often, that nobody really knows what it means anymore.

[[White Hat]] refuses to accept this, saying millennials ''are'' the college kids, to which [[Cueball]] says that maybe White Hat is the one not growing up and accepting that millennials are, in fact, adults. The title text builds on this, complaining that [[Randall]] has been having these discussions for over a decade.

White Hat has been similarly confused by what ages different generations are in [[973: MTV Generation]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[White Hat and Cueball facing each other.]
:White Hat: I'm just saying–
:White Hat: All these millennials will be in for a shock when they have to grow up and enter the real world.

:[Zoom in on Cueball's head and upper body.]
:Cueball: Except...
:Cueball: "Millennials" started reaching adulthood about 20 years ago.

:[Zoom out to full view of White Hat and Cueball facing each other in a frameless panel.]
:Cueball: Which means that some millennials can't respond to your criticism because they're busy taking their kids to check out colleges.

:[White Hat and Cueball facing each other.]
:White Hat: But ...no, millennials '''are''' college kids!
:Cueball: Maybe ''they're'' not the ones failing to grow and change over time here.

{{comic discussion}}
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Cueball]]

846: Dental Nerve

2019-06-16T19:32:11Z

Flicky: /* Explanation */

{{comic
| number = 846
| date = January 12, 2011
| title = Dental Nerve
| image = dental_nerve.png
| titletext = WAKE up in the MORning and my BREATh ain't PRETty / and noBODY'S gonna KISS me if my MOUTH smells SHItty / so I ALways brush my TEETH before I START on the JACK / sure, my DRINKing's out of HAND, but I'm conTROLLing my PLAQUE.
}}

==Explanation==
{{w|Ke$ha}} is a pop/rap singer, and this strip refers to her 2009-10 hit single "{{w|Tik Tok (song)|Tik Tok}}." The song begins with the following lyrics, of which the title text is a parody:
:Wake up in the morning feeling like {{w|P. Diddy}}
:Grab my glasses, I'm out the door, I'm gonna hit this city
:Before I leave, brush my teeth with a bottle of Jack
:'Cause when I leave for the night, I ain't coming back.

A "bottle of Jack" refers to the {{w|Jack Daniel's}} brand of whiskey.

The strip depicts Megan warning Ke$ha not to neglect dental hygiene by using whiskey instead of toothpaste to freshen her breath, due to the severe pain that could result if she let the nerves in her teeth become infected. The title text displays dental-hygiene-friendly lyrics, with emphasis on certain syllables (as all-caps) to imitate the rhythm of the original song.

==Transcript==
:Megan: Dear Ke$ha,

:Megan: It's hard to describe the pain of a deeply infected dental nerve.

:[Megan putting her hands in a bowl.]
:Megan: To get an idea, put your hands in a bowl full of ice cubes. Hold them there for 90 seconds.

:Megan: Now imagine that pain in your jaw, every minute of every hour, bright and searing, washing out everything. You can't party all night. You can barely stand up. There's only the pain.

:Megan: So, some friendly advice: When you wake up in the morning, before you brush your teeth with a bottle of Jack,

:Megan: Brush them with actual toothpaste.

{{comic discussion}}
[[Category:Comics featuring Megan]]
[[Category:Music]]

Talk:611: Disaster Voyeurism

2019-05-11T15:22:09Z

Flicky:

For reasons expounded here, I have given Black Hat my own name. "Mac" for Machiavell, a character who delights in playing the system, often to the detriment, intentional or otherwise, of others. In Mac's case, he plays the system to cause detriment. In a similar vein, Danish is "Sadie" for sadist, the literal, as opposed to literary, version of a Machiavell, and who more often causes others pain. I'm not saying these should be their names, and I will still refer them to as "Black Hat" and "Danish" on site, but I am putting my view out there. Anonymous 07:36, 4 December 2013 (UTC)
:That's very clever. [[User:Orazor|Orazor]] ([[User talk:Orazor|talk]]) 12:59, 4 June 2014 (UTC)
:: That he or she managed to circumvent the IP address monster or the revelation of the world of their own?
::Can someone please upgrade this Wikipedia entry for the likes of us dyscalculics: https://en.wikipedia.org/wiki/Potential_vorticity so that I can look cool on "Hurricane forums"?

[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 08:45, 29 January 2015 (UTC)

Surprised nobody thought to explain 'caltrop'. Sure, you can go and look it up for yourself, but doesn't that also apply to just about everything else that is 'explained' here, too? Anyway, in my experience, it's one of those words a substantial majority of folk don't know, having never heard it at all, or having not bothered to look it up. Do I just move in ignorant circles? [[Special:Contributions/108.162.246.161|108.162.246.161]] 11:37, 5 May 2017 (UTC)

You must not be a Dungeons & Dragons[https://en.wikipedia.org/wiki/Dungeons_%26_Dragons] player or at the least watched the original A-Team [https://en.wikipedia.org/wiki/The_A-Team] on TV as both in the early days Caltrops were required equipment. [[Special:Contributions/108.162.216.166|108.162.216.166]] 11:49, 28 July 2017 (UTC)

This explanation should probably explain what the three incidents mentioned in the title text are. --[[User:Flicky|Flicky]] ([[User talk:Flicky|talk]]) 15:22, 11 May 2019 (UTC)

1805: Unpublished Discoveries

2019-04-24T22:07:07Z

Flicky:

{{comic
| number = 1805
| date = March 1, 2017
| title = Unpublished Discoveries
| image = unpublished_discoveries.png
| titletext = If you must know, I'm currently researching how to save this emailed tax form as a regular PDF so I can print and sign it. Our work isn't a lock for the Nobel, but we're in the running.
}}

==Explanation==
[[Ponytail]] walks up to [[Megan]], and makes the observation that when a scientific discovery is made, it then takes a while to publish it. She then goes on to note that there are probably research teams making {{w|Nobel Prize|"Nobel-Prize-worthy"}} discoveries that have simply not been published. She is obviously curious if Megan is working on something like this, and tries to see what Megan is working on, but Megan prevents her from seeing this by partly closing her laptop. Then Ponytail asks Megan what she is doing but Megan just tells her that she isn't the one working on a project like this and ask her to "Go bother someone else."

This is not the first time Ponytail asks Megan if she is working on some groundbreaking research project: Back in [[1067: Pressures]], Ponytail was probing Megan about her work, since, as hinted by the caption of that comic, Megan is a Swiss patent clerk just like {{w|Albert Einstein}}. Ponytail thus assumes she has the same potential to produce Nobel-Prize-worthy work as him. While there is no clear indication that this comic should be a continuation of that comic or that Megan is a patent clerk, Ponytail still assumes Megan is on her way to a Nobel Prize - but that Megan is just not yet ready to announce her discovery to the public for one reason or another.

In the first two panels, [[Ponytail]] is referring to the general issue that, to publish a discovery on a scientific topic, it can take a very long time, especially when the discovery is "Nobel-Prize-worthy". Obviously the first step is for the researcher to demonstrate rigor by more supporting experiments (see [[397: Unscientific]]), plus summarize the discovery into the format accepted by the {{w|scientific journal|journal}} the {{w|scientific paper|paper}} is submitted too. The latter can take considerable time by itself, especially if the first journal the paper is submitted to declines publication. Because other journals chosen afterwards may have a completely different layout (for instance in physics, the journal with the greatest {{w|impact factor}} is {{w|Nature (journal)|Nature}}, then followed by for instance {{w|Science (journal)|Science}} and then {{w|Physical Review Letters}}. All three have very different layouts regarding format and figures etc.) Thus the paper may need to be submitted to various journals until one accepts, which may also take a few months, and even when accepted it can take anywhere from 25 days to 150+ days just for the paper to be processed through the publishing system [http://www.nature.com/news/does-it-take-too-long-to-publish-research-1.19320 due to various reasons], including the nature of the publishing process, assigning extra work as conditions for acceptance, or even formatting problems. This has prompted researchers to come up with some [http://www.phdcomics.com/comics/archive.php?comicid=926 interesting] [http://www.phdcomics.com/comics/archive.php?comicid=581 work-arounds].

In the title text, Megan claims that she is actually just trying to convert an emailed {{w|tax form}} to a PDF. This could of course just be to ward off any further attempts by Ponytail to spy on her "real" Nobel-worthy work. Megan sarcastically states that her conversion of tax forms is in the running for a Nobel Prize, perhaps because she considers it an incredibly difficult task (even for these things that should not be hard - see [[1349: Shouldn't Be Hard]]). While this could be true, this task is in no way connected to any kind of scientific endeavor, and as a result could never be considered for any kind of Nobel Prize. That the task is so difficult is though officially acknowledged by the {{w|IRS}} as they themselves note that saving and printing their [https://www.irs.com/articles/online-tax-forms Online tax forms] could be tricky. Quote:
:'''Fill-In Tax Forms'''
:''The IRS also offers Free Fillable Forms which allow you to save (and print) the information you’ve typed in online. The fill-in tax forms also require Adobe Acrobat Reader software. To save the data you’ve filled in, use the Adobe Reader’s “Save” function (not the web browser’s “Save” function). ...''

The months and weeks before April 15th (this comic was released on March 1st), is the "tax season" in the US so Americans are in the process of completing their tax forms, which is why this comic is timely. Given the US tax code is complained by many to be [http://time.com/4286921/complex-tax-code/ too complex], it is possible for researchers to delay publication of their discoveries to deal with their tax returns first. This can cause people to "sit on their discovery" for a while, although [http://www.nolo.com/legal-encyclopedia/how-much-time-do-you-spend-preparing-your-tax-return.html hopefully not as long] as the task of publishing itself.

A year after this comic, [[1971: Personal Data]] became the second tax related comic to be released in March, close to the tax day, making it two years in a row. Also before these comics the trouble with tax returns was the joke in [[1566: Board Game]], but it was released in August.

==Transcript==
:[Ponytail walks up to Megan, who is sitting in an office chair at a desk using her laptop.]
:Ponytail: When you make a big scientific discovery, it takes a while to get it published.
:Ponytail: Right?
:Megan: Mm hmm.

:[Zoom-in on Ponytail.]
:Ponytail: So there are probably several research teams out there who are sitting on Nobel-Prize-worthy discoveries, but haven't told the rest of us yet.
:Megan (off-panel): Makes sense.

:[Ponytail leans over the desk, trying to see Megan's laptop screen from behind it.]

:[Ponytail leans further. Megan pulls the screen down so Ponytail cannot see it.]
:Ponytail: Sooo... What are you working on?
:Megan: ''It isn't me!''
:Ponytail: I promise I won't tell.
:Megan: Shoo! Go bother someone else.

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Science]]
[[Category:Computers]]

1928: Seven Years

2017-12-15T13:06:12Z

Flicky:

{{comic
| number = 1928
| date = December 13, 2017
| title = Seven Years
| image = seven_years.png
| titletext = [hair in face] "SEVVVENNN YEEEARRRSSS"
}}

==Explanation==
{{incomplete|May require explaining the activities shown, as in the explanation for [[1141: Two Years]].}}
[[Randall]]'s wife was diagnosed with cancer in late 2010, a matter he has discussed in the comic [[:Category:Cancer|multiple times before]]. Here, motivated by the seven-year period between the American solar eclipses of {{w|Solar eclipse of August 21, 2017|2017}} and {{w|Solar eclipse of April 8, 2024|2024}}, we see them reminiscing the seven years prior to the first eclipse, leaving an open question to what the next seven years will bring.

This comic is a continuation of [[1141: Two Years]], which is shown as the first eight panels, slightly grayed out.

It was released as a response to another cancer diagnosis, this is explained in the [[Design_of_xkcd.com#Header_text|Header text]], which, for this comic only, has replaced the standard ''xkcd updates every Monday, Wednesday, and Friday.'' The header for this comic, with the active link included, is:
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 Vagrant]. 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.

Explanations of the individual panels:

*Panels 1–8: See [[1141: Two Years]]
*Panel 9: Randall and Randall's wife (with her hair noticeably longer than it was at the end of 1141) are walking through a forest.
*Panel 10: Randall's wife is sitting down, not in the forest anymore. She is concerned because she has pain in her toe and worries that this is an early sign of her cancer spreading again. Randall points out the simpler explanation- that she stubbed her toe the previous day, and the pain is likely a result of that. This panel shows the paranoia that comes from cancer remission, as earlier explained in [[931: Lanes]].
*Panel 11: Randall and his wife are going spelunking. The guide is gesturing deeper into the cave while Randall and his wife are climbing down.
*Panel 12: Randall's wife stands on a rock above an alligator in a swamp, photographing the alligator. Randall, on a balcony behind safety railings, observes that medical predictions about the odds of someone surviving cancer generally assume that the cancer patient doesn't risk something ''else'' killing them first.
*Panel 13: Randall's wife sits on an examination bed, listening to a doctor holding a clipboard. The doctor talks about an issue which is "probably nothing" but ''might'' be the cancer -- again showing the paranoia that comes with cancer.
*Panel 14: Randall and his wife stand above a deep pond full of fish and other objects. Randall's wife is piloting a wired underwater camera with lights. Randall shared pictures of his [https://blog.xkcd.com/2010/11/05/submarines/ underwater ROV] before.
*Panel 15: Randall and his wife are standing next to each other. Randall's wife has shoulder-length hair covering most of her face, and observes that, despite the chemotherapy robbing her of most of her hair six years ago, it is now growing enough to obscure her face. "The little girl from ''The Ring''" refers to {{w|Sadako Yamamura}}, the antagonist of the {{w|Ring (novel series)|''Ring'' series}} by {{w|Koji Suzuki}}, and popularized in a {{w|The Ring (2002 film)|2002 movie}}.
*Panel 16: A line of six people, including Randall and his wife, stand and watch the total solar eclipse of 2017, of which there have been [[:Category:Total Solar Eclipse 2017|several comics already]].
*Panel 17: The sky has been brightened, and the eclipse is over. As the eclipse is [[1880: Eclipse Review|cool to see in person]], the onlookers are left with little more than exclamations of amazement.
*Panel 18: Randall and his wife are walking together and holding hands. When his wife inquires about the next total eclipse, Randall replies that the next one is in seven years, and asks whether they should go to see it.
*Panel 19: Still walking, Randall and his wife think together about a timeline. Seven years have passed since 2010, represented with a solid line from the past to 2017; seven years in the future will be 2024, represented with a dotted line into the future and surrounded by three question marks. This is reflective of Panel 6, where "next year" is not guaranteed to be a thing.
*Panel 20: The pair keeps walking, optimistically agreeing to make their every effort to see the next eclipse.

The title text is a continuation to panel 15 concerning the horror movie ''The Ring''. Specifically, watching the videotape in ''The Ring'' is supposed to kill a person in seven days, but the title text instead says "seven years".

==Transcript==

:[The first eight panels, used earlier in the comic 1141: Two Years, are in gray color.]

:[Randall and Randall's fiancée sit on a bed, Randall's fiancée is talking on the phone. The person she is talking to, a doctor holding a clipboard, is shown inset.]
:Randall's fiancée: Oh god.

:[Randall and Randall's fiancée sit together while Randall's fiancée, now bald, is receiving chemotherapy. They are both on their laptops.]
:IV pump: ... Beeep ... Beeep ... Beeep ...

:[Randall and Randall's fiancée (who is wearing a knit cap) are paddling a kayak against a scenic mountain backdrop.]

:[Randall and Randall's fiancée sit at a table, staring at a cell phone. There is a clock on the wall. Her head is stubbly.]
:Randall's fiancée: How long can it take to read a scan!?

:[Randall and Randall's fiancée are back at the hospital again, Randall's fiancée receiving chemo. They are playing Scrabble.]
:Randall: "Zarg" isn't a word.
:Randall's fiancée: But ''caaaancer.''
:Randall: ...Ok, fine.

:[Randall and Randall's fiancée (wearing a knit cap) are listening to a Cueball-like friend. A large thought bubble is above their heads and it obscures the friends talk. The text below, split in three is the only part there can be no doubt about:]
:Friend: So next year you should come visit us up in the mounta
::a
::and
:Randall and Randall's fiancée (thinking): '''"Next year"'''

:[Randall and Randall's fiancée are getting married, with a heart above their heads. Randall's wife's hair is growing back.]

:[Randall and Randall's wife (wearing a knit cap) stand on a beach, watching a whale jump out of water. This is the last gray panel, with an additional label in normal black color.]
:''Fwoosh''
:Label: Two years

:[Randall and Randall's wife (with her hair noticably longer) are walking through a forest.]

:[Randall's wife is sitting down, not in the forest anymore.]
:Randall's wife: My toe hurts and I found a report of a case in which toe pain was an early sign of cancer spreading.
:Randall: Wait—didn’t you stub your toe yesterday?
:Randall's wife: Yes, but what if this is unrelated?

:[Randall and his wife are going spelunking. The guide is gesturing deeper into the cave while Randall and his wife are climbing down.]

:[Randall's wife stands on a rock above an alligator in a swamp, photographing the alligator. Randall is on a balcony behind safety railings.]
:Randall: When they estimated your survival odds, I think they made some optimistic assumptions about your hobbies.

:[Randall's wife sits on an examination bed, listening to a doctor holding a clipboard.]
:Doctor: This is probably nothing.
:Doctor: But given your history, we should do a full scan.
:Doctor: We'll call with the results in a few days. Try not to worry about it until then!

:[Randall and his wife stand above a deep pond full of fish and other objects. Randall's wife is piloting a wired underwater camera with lights.]

:[Randall and his wife are standing next to each other. Randall's wife has shoulder-length hair covering most of her face.]
:Randall's wife: Hard to believe—six years ago, I was bald. But today, after a long struggle, I finally look like the little girl from ''The Ring''.
:Randall: That's, uhh... good?
:Randall's wife: ''Hissssss''

:[A line of six people, including Randall and his wife, stand and watch the solar eclipse.]

:[The sky has been brightened.]
:Figure with blonde hair: ''Wow.''
:Randall's wife: Yeah.

:[Randall and his wife are walking together and holding hands.]
:Randall's wife: That was incredible.
:Randall's wife: When's the next one?
:Randall: In seven years.
:Randall: Wanna go see it?

:[Still walking, Randall and his wife think together about a timeline. Seven years have passed since 2010, represented with a solid line from the past to 2017; seven years in the future will be 2024, represented with a dotted line into the future and surrounded by three question marks.]

:[The pair keeps walking.]
:Randall's wife: Yeah.
:Randall's wife: I'll do my best.
:Randall: It's a date!

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Multiple Cueballs]]
[[Category:Comics featuring Randall Munroe]]
[[Category:Comics featuring real people]]
[[Category:Cancer]]
[[Category:Romance]]
[[Category:Total Solar Eclipse 2017]]

Talk:1879: Eclipse Birds

2017-08-21T12:12:07Z

Flicky:

Looks more like Megan is the one being sacrificed to me, instead of a generic bird - "Put her down!" would be Cueballs line then. [[Special:Contributions/162.158.90.204|162.158.90.204]] 06:35, 21 August 2017 (UTC)
:Clearly that is the joke. Have corrected this --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:07, 21 August 2017 (UTC)

It's strange the shadow is coming from the top and not from one side, isn't ? I would be frightened too... [[Special:Contributions/141.101.88.52|141.101.88.52]] 07:56, 21 August 2017 (UTC)

Would "Kachunk" and "clank clank clank" be onomatopoeia to describe the moving of the blood cauldron, rather than the bird sound? Or, given that the sounds are shown in the same manner as the rest of the bird noises, could this be the birds deliberately mimicking the sound that moving a cauldron could make? Or am I just reading in far too much into this, there is no hidden meaning, and I really need to get out more? [[Special:Contributions/141.101.107.150|141.101.107.150]] 11:17, 21 August 2017 (UTC)

Why are the "time is upon us" and "blood cauldron" lines labelled as coming from birds? I assumed they were just hysterical people talking from off-panel. --[[User:Flicky|Flicky]] ([[User talk:Flicky|talk]]) 12:12, 21 August 2017 (UTC)

1846: Drone Problems

2017-06-05T17:50:35Z

Flicky:

{{comic
| number = 1846
| date = June 5, 2017
| title = Drone Problems
| image = drone_problems.png
| titletext = On the other hand, as far as they know, my system is working perfectly.
}}

==Explanation==
{{incomplete|Possibly more, may contain language errors. Please change this comment when editing this page. Do NOT delete this tag too soon.}}

Megan is frustrated because of people flying drone too close to her. So she builds a system to shoot them down and shows it to Cueball, who clearly is also excited about the idea and helps spotting the drones. However, each of the drones gets accidentally destroyed by its own user because of their inability to fly the drones.

After three hours of unsuccessful drone hunting, frustrated Megan complains about people unable to fly the drones, which prevents her (and Cueball) from having fun shooting them down. The joke is that she originally created the system to get rid of the drones, so lack of drones should be the desired output - and now she wants the drones nearby (even if only temporarily).

The title text refers to the fact that from an outsider's perspective, the system is keeping every drone away from the house.

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

Megan is sitting on her porch when Cueball comes walking up.

:Megan: People in the park keep flying drones near me, so I've built a system to shoot them down.
:Cueball: Cool! Oh yeah, there's one now.
:Megan: Time for a test!

:Megan: Okay, locking on…
:Cueball: Wait, it just crashed.
:Megan: Damn.

:Cueball: Here comes another one! Aim for… nope, it got stuck in a tree.

:Caption: Three hours later…
:Cueball: Finally, two more just—no, one crashed and the other is hurtling sideways toward the lake.
:Megan: ''Will you people learn to fly these things?!''

{{comic discussion}}

[[Category:Drones]]

1843: Opening Crawl

2017-05-29T15:58:57Z

Flicky: Undo revision 140478 by 162.158.89.19 (talk)

{{comic
| number = 1843
| date = May 29, 2017
| title = Opening Crawl
| image = opening_crawl.png
| titletext = Using a classic Timothy Zahn EU/Legends novel is bad enough, but at least the style and setting aren't too far off. If you really want to mess with people, try using Splinter of the Mind's Eye.
}}

==Explanation==
{{incomplete|I have a bad feeling about this.}}

Each episodic {{w|Star Wars}} film begins with an "{{tvtropes|OpeningScroll|opening crawl}}" giving the audience some of the backstory, which often reads like the prologue of a novel.

Randall wants to reverse this by projecting the text of a Star Wars novel and see how long this can be continued before viewers realize it is a prank.

The tile text compares different Star Wars novels' style, remarking on how well suited they would be for this prank.

{{w|Timothy Zahn}} is a science fiction writer who has written and contributed to many novels and comics [http://starwars.wikia.com/wiki/Timothy_Zahn#Works] in the {{w|Star Wars expanded universe}}. The text in the comic is from the book ''[http://starwars.wikia.com/wiki/The_Last_Command The Last Command]''.

''[http://starwars.wikia.com/wiki/Splinter_of_the_Mind%27s_Eye Splinter of the Mind's Eye]'' was an early Star Wars novel written before the original film was expanded to a trilogy (and then expanded some more), so it contains multiple aborted subplots which can make it very confusing for a fan who has seen the later works.

The term "EU" refers to "Expanded Universe", which was the term for the corpus of non-cinematic ''Star Wars'' content before ''Star Wars'' was acquired by {{w|Disney}}. Not wanting to be constrained by previous canon, Disney declared all "Expanded Universe" content to be non-canonical, and re-branded the EU as "Legends".

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

''Text taken from Book 3 of the "Thrawn" trilogy[http://www.glozman.com/TextPages/Star%20Wars%20-%20%5BThrawn%20Trilogy%2003%5D%20-%20The%20Last%20Command%20(by%20Timothy%20Zahn).txt]''

'''Chapter 1'''

Gliding through the blackness of deep space, the Imperial Star Destroyer Chimaera pointed its mighty arrowhead shape toward the dim star of its target system, three thousandths of a light-year away. And prepared itself for war.

"All systems show battle ready, Admiral," the comm officer reported from the portside crew pit. "The task force is beginning to check in."

"Very good, Lieutenant," Grand Admiral Thrawn nodded. "Inform me when all have done so. Captain Pellaeon?"

"Sir?" Pellaeon said, searching his superior's face for the stress the Grand Admiral must be feeling. The stress he himself was certainly feeling. This was not just another tactical strike against the Rebellion, after all—not a minor shipping raid or even a complex but straightforward hit-and-fade against some insignificant planetary base. After nearly a month of frenzied preparations, Thrawn's master campaign for the Empire's final victory was about to be launched.

But if the Grand Admiral was feeling any tension, he was keeping it to himself. "Begin the countdown," he told Pellaeon, his voice as calm as if he were ordering dinner.

{{comic discussion}}

[[Category:Star Wars]]

1785: Wifi

2017-01-13T06:12:39Z

Flicky: /* Explanation */

{{comic
| number = 1785
| date = January 13, 2017
| title = Wifi
| image = wifi.png
| titletext = Further out to the right, it works correctly, but the reason it works still involves the word 'firmware.'
}}

==Explanation==
{{incomplete| first edit}}

The graph shows the probability that a guest will be able to connect to the owner's wifi. The large drop involves firmware. Firmware is an extra layer that sits between the operating system and the device, in this case a wifi card. In most systems this just works but in the case of more geeky operating systems, like GNU/Linux, it needs to be installed separately. Therefore there are a group of people who know what they are missing but are unable to overcome the issue to connect. The title text indicates that the curve recovers once users are more experienced.

These computer issues have previously appeared in several XKCD comincs, notably [[456: Cautionary]].

==Transcript==
{{incomplete transcript}}

{{comic discussion}}