explain xkcd - User contributions [en]

3090: Sail Physics

2025-05-17T07:42:01Z

172.70.91.181: /* Explanation */ "are of electromagnetic in nature" is a mish-mash, properly either "are electromagnetic in nature" or "are electromagnetic in nature".... went with the first.

{{comic
| number = 3090
| date = May 16, 2025
| title = Sail Physics
| image = sail_physics_2x.png
| imagesize = 699x263px
| noexpand = true
| titletext = Turning in other directions can be accomplished by using a magnetized centerboard and ocean currents, since a current flowing through a magnetic field induces a Laplace force.
}}

==Explanation==
{{incomplete|This page was created by a wind-blown electron. Don't remove this notice too soon.}}

This comic shows what initially appears to be an explanation of how boats sail upwind. However, it quickly devolves into wrongness, where, instead of even mentioning {{w|tacking (sailing)|tacking}}, it dives into a totally wrong explanation involving electrons and magnetism.

This humour works at another level — almost all interaction of physical things with each other at macro scale (humans and boat sized objects) are electromagnetic in nature (this is considering, that at this scale, among the 4 fundamental interactions, only electromagnetic interactions are of reasonable strength). So one unaware of sailing mechanics may start to explain the situation with electromagnetism, and could come to this line of thinking, but it is wrong. If we are to consider this, we find that either no force is appearing in the direction shown, or very little.

{{w|Triboelectric effect|Triboelectric effect}} is the mechanism of acquisition of static charge. Though, it depends on relative frictional forces involved between two objects, which in turn depends on effective interaction surface area. But the charge acquired would be very small, and not be of comparative order of magnitudes with gravity. There is more charge generated due to running of water across the boat in a realistic situation. Then the comic assumes motion in the direction of downstream, due to effective normal forces on the sail. Then the comic considers this motion as motion of a charged object in Earth's magnetic field. If we are to consider this magnetic field to be roughly parallel to Earth's surface, which would be true for situations close to the equator (as Earth's magnetic field is effectively that of dipole bar magnet, which is roughly aligned with our planetary rotational axis (as of writing of this explanation, as the magnetic field dipole keeps on moving, and this may change)). The net Lorentz force on the boat would be F = qvB, and since both velocity of both and magnetic field lines are in the same plane (as viewed in the above sketches, in a top-down manner), then the force would be perpendicular to the plane. That is, along the direction of gravity for the boat, which will not cause any motion in plane. If we consider magnetic field lines to be perpendicular to Earth's surface (close to poles), even then the magnitude of the force is very small. If we consider a net charge of 1 coulomb across the boat (which is an extremely high amount of charge, at which point, the charge would try to accumulate on sharp objects, and due to this high charge density, either charge will leave the boat through coronal discharge, or the sharp objects would start to break from the boat (this is due to high self electrostatic energy, which is roughly proportional to square of charge density divided by radius of curvature of object, if the bonding between object is not strong enough, then this electrostatic energy can overcome this bonding energy), assuming that this charge does not cause the ship to break or the charge to leak out to water body, as the charge would like to spread to minimise the electrostatic energy), and if we consider field strength of order 0.0001 Tesla (close to typical values on surface), and take wind speeds of 10000 m/s (also very high) then the net force on ship would be 1 N, which for a boat of mass 10 kg (less for a typical boat, but is appropriate for a makeshift raft) cause a net acceleration of 0.1 m/s^2. Which is not tiny, but due to friction across the boat, would be cancelled out (by 1 or 2 orders of magnitude). This is considering the best possible case. For more reasonable charge values, this force would be about a trillion times weaker, and hence this will not cause any practical motion.{{citation needed}}

If the described effect were actually significant, it wouldn't always make boats turn upwind. A positively charged boat would turn counter-clockwise on the northern hemisphere, where the magnetic field points down, and clockwise on the southern hemisphere, where the magnetic field points up. Thus it would turn upwind or downwind depending on which side of the boat faces the wind. A negatively charged boat would turn in the opposite direction. To beat to windward it would be necessary to switch between two sails made of different materials – one sail to accumulate a positive charge, and another to accumulate a negative charge.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

[Panel 1]

How sailboats use physics to sail upwind:

[A schematic boat with a sail is shown (top-down view). Winds shown with directional arrows, pointing in the direction of the sail (going towards 4:30 on a clock face).]

[Panel 2]

1. Wind passing over the sail strips away electrons via the triboelectric effect.

[Schematic similar to panel 1, but with charged ions shown across both sides of the sail, representing the triboelectric effect.]

[Panel 3]

2. The positively charged boat is blown downwind; its movement in Earth's magnetic field produces a Lorentz force.

[The same schematic, except a force vector is shown in the direction of the wind, and a perpendicular force vector (along 1:30 on a clock face) is shown with a dashed arrow.]

[Panel 4]

3. The Lorentz force acts perpendicular to the direction of motion, redirecting the boat upwind.

[A net force vector is shown perpendicular to the downstream vector.]

{{comic discussion}}<noinclude>

Talk:3078: Anchor Bolts

2025-04-19T09:49:21Z

172.70.91.181:

As a kid, I was ALWAYS worried about how plate tectonics would change the continent's layout in a few hundred million years' time, along with how the Sun will die (and maybe consume the Earth if we don't move it) in five billion years. Young me would be SO glad we are finally fixing the first issue. [[User:MinersHavenM43|MinersHavenM43]] ([[User talk:MinersHavenM43|talk]]) 03:28, 19 April 2025 (UTC)
: Was young you a Superman fan, and did you ever wonder what really happened on Krypton? Scientists and engineers, funded and enabled by a Trump-style politician and his promise to "Stop The Earthquakes NOW!", actually overcame (temporarily) the materials issues and solved the stress equations (see below), and installed a (temporarily) successful planetary plate-anchoring system. Jor-El objected to the project, he and any who supported him were de-funded as a result, and he spent his remaining time ensuring that he could get his son the [deleted] outa there before the accumulated strain ruptured the anchors and blew the planet apart. [[Special:Contributions/162.158.41.45|162.158.41.45]] 04:09, 19 April 2025 (UTC)
:Did you also worried about the collision with Andromeda galaxy? -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 05:15, 19 April 2025 (UTC)

Would an anti-subduction screw really work? The tectonic plates are slow, but they are quite heavy, so they have a fair bit of momentum. Indeed, enough to overcome the not inconsiderable friction already present due to the weight of the uplifted portion of the upper plate. Such a screw would therefore need to exert quite a bit of additional pressure to bring the motion to a halt; Exactly how much I shall leave as an exercise for the reader (because I have no clue where to even start trying to work it out), but my guess is that you're gonna need some seriously high tensile strength material for these, even if they are placed at very short intervals along the plate boundary. [[Special:Contributions/172.68.84.172|172.68.84.172]] 03:52, 19 April 2025 (UTC)

:The screw material could easily be some sort of unobtanium, it would still not work. With the forces involved, the result would be the stone would break around the screws, IMHO. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 05:16, 19 April 2025 (UTC)

Looks like somebody got to Randall M. and pointed out that what he drew is a {{w|Bolt_(fastener)|bolt}}, not a screw. The title and caption of the comic have been edited accordingly. [[Special:Contributions/162.158.41.3|162.158.41.3]] 05:38, 19 April 2025 (UTC)

:The item depicted is a 'machine screw'; A bolt has a portion of the shaft un-threaded. An actual bolt would likely be more suitable for this application, but it's not uncommon for machine screws to be used instead.[[Special:Contributions/172.69.23.21|172.69.23.21]] 09:21, 19 April 2025 (UTC)

This is silly. The global cooperation and engineering required to make this work (I'm assuming unobtanium as a given) far surpasses that required to decarbonise commerce and fix climate change, which project is not going well, to say the least. [[User:Neil UK|Neil UK]] ([[User talk:Neil UK|talk]]) 08:32, 19 April 2025 (UTC)

Added an Actual Citation Needed to vulcanism being bad for humanity. Without it, life may not have started in the first place. And fertile volcanic soils would not have sustained us/our predecessors if such life had started. Minor issues like localised danger are surely a blip in time compared to that, and even now there's only a danger to ''some'' humans (less than, say, yellowstone erupting, which isn't something a bolt could stop... in fact, drilling the bolthole sounds like it could ''cause'' a Yellowstone, if done wrongly (if, in fact, there is a 'right' way)). ...other than that, yeah, go ahead! [[Special:Contributions/172.70.91.181|172.70.91.181]] 09:49, 19 April 2025 (UTC)

Talk:3073: Tariffs

2025-04-08T13:09:35Z

172.70.91.181:

Uh, still no April fools [[User:Aprilfoolsupdate!|Aprilfoolsupdate!]] ([[User talk:Aprilfoolsupdate!|talk]]) 23:50, 7 April 2025 (UTC)
:The April fools is the president the U.S. Elected. (note: I am Usanian)[[Special:Contributions/172.70.214.232|172.70.214.232]] 12:41, 8 April 2025 (UTC)
I felt like using all caps is a good idea for explanations, since the comic itself is all caps [[User:Aprilfoolsupdate!|Aprilfoolsupdate!]] ([[User talk:Aprilfoolsupdate!|talk]]) 00:03, 8 April 2025 (UTC)
: Please don't. If you did that, then all of the other explanations and transcripts would have to be edited to all-caps, which makes it harder to read. [[User:Firestar233|guess who]] ([[User talk:Firestar233|if you desire conversing]] | [[Special:Contributions/Firestar233|what i have done]]) 01:07, 8 April 2025 (UTC)
:Doesn't just about ''every'' xkcd comic use all-caps? That would make pretty much the entire wiki unreadable. [[Special:Contributions/172.71.155.35|172.71.155.35]] 04:15, 8 April 2025 (UTC)

What's wrong with the explanation? It's showing this weird string of letters: expDia thud enzo Isla idiosyncrasies talk 3totheaudienceandtheotherswhoareyouheresoearlyinthedayafterMittenslefttodois sign up for both ofuscan'twaitforthemostparttobeabrightandwarmwelcomeandIhopethatyouwillfindapenthatwillOrbitz pap [[Special:Contributions/162.158.159.8|162.158.159.8]] 20:23 7 April 2025 EST
: Vandals --[[User:Btx40|Btx40]] ([[User talk:Btx40|talk]]) 00:32, 8 April 2025 (UTC)
::I'm getting a few Cloudflare messages that the server isn't responding. I'm used to explainxkcd giving straight 503s, etc, but this is the kind of thing (code 522, in at least one case) that you get only when an active pressure (crap-spamming, etc) is being applied. I'm wondering if there's some pushback from the pro-tariff (or at least 'pro-Donald') online community. [[Special:Contributions/172.70.85.32|172.70.85.32]] 11:12, 8 April 2025 (UTC)

Hopefully, just HOPEFULLY, we can prevent the comment section from devolving into insults like https://xkcd.com/1756/: I'm With Her. [[User:Thehydraclone|Thehydraclone]] ([[User talk:Thehydraclone|talk]]) 01:51, 8 April 2025 (UTC)
:I concur, though I want to stress that I think it's very important that we try to make this comic explanation as neutral as possible. Is it possible to not show a bias towards either side of the issue? Randall's comic obviously has a point of view, but perhaps the explanation on this site can be a little bit more neutral. [[User:Dogman15|Dogman15]] ([[User talk:Dogman15|talk]]) 11:41, 8 April 2025 (UTC)
:You stink! [[Special:Contributions/172.70.91.181|172.70.91.181]] 13:09, 8 April 2025 (UTC)

Comic [[2566]] was supposed to be a joke... --[[Special:Contributions/172.68.175.87|172.68.175.87]] 03:58, 8 April 2025 (UTC)

"venmo" needs explaining. Apparently it's some sort of USAian proprietary payment system? And I think Ponytail's company is providing a service (which the USA exports of lot of), rather than selling equipment - services usually not being captured by simple trade figures for goods. And in order to post here I have to identify features of foreign street scenes in order to train a monopolist's proprietary image recognition system. [[Special:Contributions/162.158.216.115|162.158.216.115]] 13:03, 8 April 2025 (UTC)

2367: Masks

2025-03-04T20:45:37Z

172.70.91.181: /* Explanation */ Grammar (and, for the sake of not repeating, a little further edit).

{{comic
| number = 2367
| date = October 2, 2020
| title = Masks
| image = masks.png
| titletext = Haunted Halloween masks from a mysterious costume shop that turn you evil and grow into your skin score a surprisingly high 80% filtration efficiency in R. L. Stine-sponsored NIOSH tests.
}}

==Explanation==
This comic is another in a [[:Category:COVID-19|series of comics]] related to the {{w|COVID-19 pandemic}}.

This comic is a line from top to bottom explaining how good different types of masks are at preventing respiratory virus transmission. This comic may have been inspired from [https://www.polygon.com/entertainment/2020/5/15/21259215/how-to-wear-masks-superhero-costumes-coronavirus-effectiveness a Polygon article published on May 15th].

===Types of masks===
*'''{{w|Zorro}}'''/'''{{w|Lone Ranger}}''': A strip of cloth around the eye-level. Since it does not cover the mouth and nose, the main ways the virus leaves the body to infect others, or the mouth, nose and eyes, the main ways it enters the body, it is ineffective and no better than wearing no mask at all.
*'''{{w|Batman}}''': Batman's iconic headgear has gone through many revisions, and consists either of a simple cloth cowl or a helmet and visor. Does not cover the mouth, but may cover the nose. However, the mask only covers the top part of the face, i.e., not the mouth or nostrils. This mask might be slightly more effective than the Lone Ranger style mask due to the intimidation effect keeping other people back, and depending on its length, it might help direct air that the wearer breathes out down instead of towards others' faces, which would reduce the risk of spreading any respiratory diseases that the wearer may be infected with.
*'''Theater masks''' ({{w|Sock and buskin}}): Traditionally used as a symbol of performance theater since ancient Greece. The eye and mouth holes are often open, thus exposing the wearer.
*'''Skincare''' ({{w|facial mask}}): A layer of mud or moisturizer. By nature, it does not cover the mouth or nostrils, but it may keep the wearer from touching their face and is usually worn by someone sitting in a chair or lying back on a bed, not out getting in other people's personal space.
*'''Scarecrow''': A burlap sack. While it provides some cover to the mouth and nose, it is heavily porous. This could also refer to the {{w|Scarecrow (DC Comics)|Scarecrow}}, a DC Comics villain. If so, the mask would probably be much more effective than an ordinary burlap sack, as that character uses airborne drugs as weapons, and would have to have very good filter ability to protect himself.
*'''{{w|Guy Fawkes mask}}''': A plastic mask that is a stylized depiction of {{w|Guy Fawkes}} (designed by David Lloyd for the comic book ''{{w|V for Vendetta}}'' and made popular by {{w|V for Vendetta (film)|its movie adaptation}} and subsequent adoption by the {{w|Anonymous (group)|Anonymous}} movement). Most Guy Fawkes masks provide small holes in the front for comfort, thus facilitating spread of the virus.
*'''{{w|Cloth face mask|Cloth}}''': A cloth mask that blocks most large particles, like virus-laden saliva. To be most effective, it must cover nose as well as the mouth. These are much cheaper than N95 masks, and can be reused by washing. Not all cloth masks are created equal, some designs and materials are more effective than others at holding back contagious particles, but Randall lists them under "Effective" on the whole. They are relatively effective at preventing the wearer from infecting others, but are less effective at protecting the wearer from being infected by others, because droplets leaving the body are large enough to block, but small enough to get through cloth after evaporation. The felt-like nonwoven fabric of surgical masks blocks more droplets and aerosols than the same thickness of knit or woven fabric.
*'''{{w|Spider-Man|Spiderman}}'''''[sic]'': A full face covering of spandex-like material (Spider-Man comics rarely if ever specify what material Spider-Man makes his costume from). Would block most virus particles. (The correct spelling is "Spider-Man", with a hyphen, and "Man" capitalized.)
*'''{{w|N95 mask|N95}}''': A standard air filtration mask, commonly used in industry but also used in healthcare. The name "N95" signals that it is not resistant to oil, but successfully filters 95% of airborne particles. It has proven to be one of the more successful masks during the 2020 pandemic. N95 masks usually include non-woven filtration material, which while often stiff like cardstock, is more similar to the felt-like fabric of surgical masks than to woven cloth. N95 masks can [https://youtu.be/eAdanPfQdCA filter particles much smaller] than the gaps between layers and strands in the fabric.
*'''{{w|scuba set|SCUBA}}''': A '''S'''elf-'''C'''ontained '''U'''nderwater '''B'''reathing '''A'''pparatus. Most SCUBA equipment used an open-circuit design allowing exhaled air to vent to the atmosphere. Underwater, this would not be a threat to other divers who would also be breathing air from their tanks. However, on land a typical SCUBA regulator would expose others to virus particles. Closed-circuit SCUBA equipment recirculates the user’s gas supply but they still contain a means of venting extra gas into the atmosphere. Neither system contains expiratory HEPA filters making both ineffective at preventing virus transmission. That all said, SCUBA equipment still covers the face and nose, rather than directly exposing others to unshielded breathing and coughing.
*'''{{w|Darth Vader|Vader}}''': Reference to one of the main antagonists in {{w|''Star Wars''}}, in which he wears a suit of armor with a built-in rebreather. Similar to SCUBA gear, it circulates air back to the user, in order to defend against the spread of the virus to the wearer. The question of whether Vader's mask would protect against COVID was implicitly referenced again in [[2441: IMDb Vaccines]].
*'''{{w|Mysterio}}''': Reference to one of the antagonists in ''{{w|Marvel Comics}}''’ {{w|Spider-Man}} as part of the {{w|Sinister Six}}. He wears a glass helmet. In the comics Mysterio often uses mind-altering chemicals, and his suit is designed to shield himself from his own weapons. By the same design, it would shield himself and others from the spread of viral infection. He might also not even be in your presence if, especially as in the film version, the Mysterio you see is himself currently an illusion.
*'''Haunted Halloween Masks''': The title text is a reference to ''{{w|The Haunted Mask}}'' by {{w|R. L. Stine}}, a book in the {{w|Goosebumps (original series)|''Goosebumps'' series}}. The mask transforms the wearer into a monster, with an open (uncovered) nose and mouth. The test results claim that the wearer is still somehow substantially protected against inhaling virus particles, but this may be a fraudulent test result due to pressure from the sponsor of the test, R. L. Stine, to get more people to wear such masks; it is also possible that the supernatural effects somehow include blocking virus particles, as parasites generally benefit from keeping their hosts alive and healthy, at least in the short term; it is further possible that, due to wearers having a stronger immunity in monster-form, they simply defeat the virus even before suffering its symptoms. NIOSH refers to the ''{{w|National Institute for Occupational Safety and Health}}''.

==Position on chart==
*[With 0% at the top position of the top arrow and 100% effective at the position of the bottom arrow the masks effectiveness would be approximately as follows:]
:[02%] Zorro/Lone Ranger
:[03%] Batman
:[07%] Theater
:[10%] Skincare
:[15%] Scarecrow
:[18%] Guy Fawkes
:[48%] Cloth
:[52%] Spider-Man
:[68%] N95
:[71%] Scuba
:[80%] Vader
:[90%] Mysterio

==Transcript==
:[A chart is shown with a title and explanation at the top:]
:<big>'''Masks'''</big>
:By effectiveness at preventing respiratory virus transmission

:[The chart consist of a vertical line going top to bottom with arrows at both ends. There are labels at the top, around the middle and at the bottom:]
:Not effective.
:Effective
:Extremely Effective

:[Along the line there are 12 bullets. From each bullet there goes a line (often with one or two turns) to a depiction of a type of mask. Each mask type is labeled. The first six masks are all close to the top, the last only halfway down to the middle of the line. The next two are right around the middle, then two are halfway towards the bottom from there and the final two are close to the bottom, with the last very close to the botom. From top to bottom:]
:Zorro/Lone Ranger
:Batman
:Theater
:Skincare
:Scarecrow
:Guy Fawkes
:Cloth
:SpiderMan
:N95
:Scuba
:Vader
:Mysterio

{{comic discussion}}

[[Category:COVID-19]]
[[Category:Comics featuring face masks]]
[[Category:Charts]]
[[Category:Rankings]]
[[Category:Fiction]]
[[Category:Star Wars]]

3054: Scream Cipher

2025-02-25T09:39:50Z

172.70.91.181: /* Explanation */

{{comic
| number = 3054
| date = February 21, 2025
| title = Scream Cipher
| image = scream_cipher_2x.png
| imagesize = 287x416px
| noexpand = true
| titletext = AAAAAA A ÃA̧AȂA̦ ǍÅÂÃĀÁȂ AAAAAAA!
}}

==Explanation==
{{incomplete|Created by A ÃA̧ȂÁAǍẢÂA̋ ȦÅĀ - Need to add more notes for the other cipher characters. Do NOT delete this tag too soon.}}
A {{w|Cipher}} is a method of encryption, where characters, or sometimes words, are substituted for other characters in a set pattern, allowing for arbitrary strings to be enciphered using it. The complexity and strength of ciphers varies, from {{w|one-time pads}} and (historically) {{w|enigma machine|Enigma}} as stronger and more complex, to {{w|substitution ciphers}} as some of the weakest and least complex, where each character is simply given a set different symbol to represent it in the cipher.

This comic uses a substitution cipher, where all the letters of the English Alphabet are represented using the letter "A", with different {{w|diacritical marks}} to define the differences. See details about the 25 marks in the [[#Trivia|Trivia section]] below. This kind of cipher is often used on a recreational basis by children or casual enthusiasts, the similarity of the letters increasing the obscurity of the content and the skill or technology required for use, but there is also significant impracticality, as not only are substitution ciphers the easiest to break, but also the similarities in the letters do make the cipher hard to read and easy to misread, and the detail in the diacritical marks makes it easy to draw the "A"s incorrectly or ambiguously, potentially leading to [[3003: Sandwich Helix|part of the message being lost]]. This was our experience in the comments section of this very article, where one person implemented translator functions alongside another person crafting a message that failed to translate. However, the logic behind the code is mostly visual similarity, and if attentive to connecting concepts between the Latin and scream cipher alphabet, it could be quickly learned and translated in a glance.

It's named "Scream Cipher" (as a pun on {{w|stream cipher}}s, commonly used in computing) because the written form of a scream is a long string of As, possibly with some other characters at the end (and often an exclamation point for emphasis), such as "Aaaaaah!" or "Aaaaaaagh!". The name may or may not be a reference to IBM's {{w|Scream_(cipher)|Scream cipher}} published in 2002.

In the comic, [[Cueball]] texts the ciphered version for the plaintext "HELLO", and [[Megan]] responds with that for "HI".

The title text deciphers to "AAAAAA A SCARY MONSTER AAAAAAA!"

You can translate text to and from Scream Cipher using [https://github.com/matthewpwatkins/scream-cipher/ the Scream Cipher Translator] or [https://github.com/Reginald-Gillespie/ScreamCipher any other] [https://github.com/klanderfri/ScreamCipher/ alternative] with additional features.

Another recent comic featuring all "A"s was [[2957: A Crossword Puzzle]].

Diacritics was also the main theme in [[1647: Diacritics]] (of course) and was previously also mentioned in [[1209: Encoding]] and in [[1857: Emoji Movie]] where they have an important part of the pun, and is mentioned in one point of the list in [[1957: 2018 CVE List]].

==Worked example==

Say we want to encode "Scream" in the Scream Cipher. First we would need to split out word into the letters, so S, C, R, E, A, M.

The first letter is S, so if we go to S in the table S is shown to become to Ã, C similarly becomes A̧, R becomes Ȃ, E corresponds to Á, A is the main letter so A is unchanged to A, and M becomes Ǎ. If we then write them again in order, we find SCREAM becomes ÃA̧ȂÁAǍ.

To turn cipher text back into normal text, the process is repeated in reverse. To translate A̧ẢA̯A̰ÁȂ, we go to A̧ in the table and find A̧ becomes C. Ả similarly becomes I, A̯ becomes P, A̰ becomes H, Á becomes E, and Ȃ becomes R. If we write the letters in order, we see that A̧ẢA̯A̰ÁȂ becomes CIPHER.

==Transcript==
:[The top of the panel has the 26 letters of the alphabet written, each followed by a hyphen and the letter "A" with a unique diacritical mark for each. "A - A" is the only letter in the top row, and the only one where that A on the right side doesn't have a diacritic. The next 25 is sorted in a 5 by 5 grid, with the first five letters after A in the first column, then the next 5 in the second column and so on:]
:{|
|A - A
|-
|B - Ȧ
|G - A̋
|L - Ă
|Q - A̤
|V - À
|-
|C - A̧
|H - A̰
|M - Ǎ
|R - Ȃ
|W - Ȁ
|-
|D - A̱
|I - Ả
|N - Â
|S - Ã
|X - A̽
|-
|E - Á
|J - A̓
|O - Å
|T - Ā
|Y - A̦
|-
|F - A̮
|K - Ạ
|P - A̯
|U - Ä
|Z - Ⱥ
|}
:[Beneath these letters we see Cueball and Megan typing on their phones, Cueball with two hands and Megan with one hand, small lines indicating the movement of their hands. Cueball and Megan is turned towards each other but with more separation than if they were engaged in normal discussion. They both look down at their phones not towards each other. The text they type is shown above their phone with a line starting in a starburst at the top of their phones going up the to the text.]
:Cueball's phone: A̰ÁĂĂÅ
:Megan's phone: A̰Ả

:[Caption below the panel:]
:In the '''''Scream Cipher''''', messages consist of all As, with different letters distinguished using diacritics.

==Trivia==
The {{w|Unicode}} names of the characters in the cipher are as follows:

{|class="wikitable"
! colspan=2 | Input !! colspan=3 | Substitution
|-
! Plain !! Unicode description !! Cipher !! Unicode description(s) !! Notes
|-
| A || U+0041 LATIN CAPITAL LETTER A || {{w|A}} || '''U+0041 LATIN CAPITAL LETTER A || Unadorned base character
|-
| B || U+0042 LATIN CAPITAL LETTER B || {{w|Ȧ}} || '''U+0226 LATIN CAPITAL LETTER A WITH {{w|Dot (diacritic)|DOT}} ABOVE || A with one dot over it, which can indicate a single change in math and science. Phonetic symbol for low central vowel.
|-
| C || U+0043 LATIN CAPITAL LETTER C || A̧ || U+0041 LATIN CAPITAL LETTER A, '''U+0327 {{w|Combining Diacritical Marks|COMBINING}} {{w|Cedilla|CEDILLA}}''' || Cedilla is often attached to a 'c', as in "français", as well as starting with 'c' itself.
|-
| D || U+0044 LATIN CAPITAL LETTER D || A̱ || U+0041 LATIN CAPITAL LETTER A, '''U+0331 COMBINING MACRON BELOW''' || Some see the lower bar as similar to the lower edge of the D.
|-
| E || U+0045 LATIN CAPITAL LETTER E || {{w|Á}} || '''U+00C1 LATIN CAPITAL LETTER A WITH ACUTE || Many words have an acute e, as in "fiancé".
|-
| F || U+0046 LATIN CAPITAL LETTER F || A̮ || U+0041 LATIN CAPITAL LETTER A, '''U+032E COMBINING BREVE BELOW''' || The breve adds a second line to the A, much like how an F has two lines.
|-
| G || U+0047 LATIN CAPITAL LETTER G || A̋ || U+0041 LATIN CAPITAL LETTER A, '''U+030B COMBINING {{w|Double acute accent|DOUBLE ACUTE}} ACCENT''' || Adds two acutes to a letter.
|-
| H || U+0048 LATIN CAPITAL LETTER H || A̰ || U+0041 LATIN CAPITAL LETTER A, '''U+0330 COMBINING TILDE BELOW''' || The low tilde has horizontal ink in the middle that moves vertical toward the sides, like an H.
|-
| I || U+0049 LATIN CAPITAL LETTER I || {{w|Ả}} || '''U+1EA2 LATIN CAPITAL LETTER A WITH HOOK ABOVE || The hook almost looks like half of a circle, and the lowercase letter I (i) has a circular shape (known as a tittle) above it.
|-
| J || U+004A LATIN CAPITAL LETTER J || A̓ || U+0041 LATIN CAPITAL LETTER A, '''U+0313 COMBINING COMMA ABOVE''' || The comma symbol looks like a small letter 'J' in some fonts
|-
| K || U+004B LATIN CAPITAL LETTER K || Ạ || '''U+1EA0 LATIN CAPITAL LETTER A WITH DOT BELOW || 
|-
| L || U+004C LATIN CAPITAL LETTER L || {{w|Ă}} || '''U+0102 LATIN CAPITAL LETTER A WITH {{w|Breve|BREVE}} ||
|-
| M || U+004D LATIN CAPITAL LETTER M || Ǎ || '''U+01CD LATIN CAPITAL LETTER A WITH {{w|caron|CARON}} || The top-centered caron is the same shape as the top center of the M.
|-
| N || U+004E LATIN CAPITAL LETTER N || {{w|Â}} || '''U+00C2 LATIN CAPITAL LETTER A WITH CIRCUMFLEX || The lowercase letter 'n' also looks like a circumflex in some scripts. The circumflex peak mirrors the peak at the top left of the N.
|-
| O || U+004F LATIN CAPITAL LETTER O || {{w|Å}} || '''U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE || The symbol contains the letter 'O'. In Scandinavian languages like Swedish, this combination of 'O' and 'A' is a letter unto itself, mostly used in words where a long 'a' sound has acquired a more 'o'-like sound.
|-
| P || U+0050 LATIN CAPITAL LETTER P || A̯ || U+0041 LATIN CAPITAL LETTER A, '''U+032F COMBINING INVERTED BREVE BELOW''' || Refer to R: P also has a curve at the top center, but is encoded with one below.
|-
| Q || U+0051 LATIN CAPITAL LETTER Q || A̤ || U+0041 LATIN CAPITAL LETTER A, '''U+0324 COMBINING DIAERESIS BELOW''' || The two dots below the baseline reflect the two times Randall's Q touch the baseline. In the Orthographies of Spanish, Catalan, French and Galician, the grapheme 'qu' normally represents a single sound, before vowels 'e' and 'i'. In the few exceptions where the 'u' is pronounced, a diaeresis is added to it.
|-
| R || U+0052 LATIN CAPITAL LETTER R || Ȃ || '''U+0202 LATIN CAPITAL LETTER A WITH {{w|Inverted breve|INVERTED BREVE}} ||
The inverted centered top curve mirrors the curve at the top center of an R.
|-
| S || U+0053 LATIN CAPITAL LETTER S || {{w|Ã}} || '''U+00C3 LATIN CAPITAL LETTER A WITH TILDE || Tilde looks like a sideways 'S'.
|-
| T || U+0054 LATIN CAPITAL LETTER T || {{w|Ā}} || '''U+0100 LATIN CAPITAL LETTER A WITH {{w|Macron (diacritic)|MACRON}} || The macron looks like the top horizontal line in the letter 'T'
|-
| U || U+0055 LATIN CAPITAL LETTER U || {{w|Ä}} || '''U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS || Many German and Swedish words have a 'Ä', as in "{{w|Die_Ärzte|Ärzte}}". Similar to the encoding for Q, the two top dots mirror the two times the script of U reaches the top line.
|-
| V || U+0056 LATIN CAPITAL LETTER V || {{w|À}} || '''U+00C0 LATIN CAPITAL LETTER A WITH GRAVE || Grave has the letter 'V' in it, as well as being half of its shape.
|-
| W || U+0057 LATIN CAPITAL LETTER W || Ȁ || '''U+0200 LATIN CAPITAL LETTER A WITH {{w|Double grave accent|DOUBLE GRAVE}} || The letter 'W' is visually two copies of the letter 'V'
|-
| X || U+0058 LATIN CAPITAL LETTER X || A̽ || U+0041 LATIN CAPITAL LETTER A, '''U+033D COMBINING X ABOVE''' || The symbol contains the letter 'X'.
|-
| Y || U+0059 LATIN CAPITAL LETTER Y || A̦ || U+0041 LATIN CAPITAL LETTER A, '''U+0326 COMBINING COMMA BELOW''' || Comma is used con conjuntion as the letter 'Y' in some languages like Spanish
|-
| Z || U+005A LATIN CAPITAL LETTER Z || {{w|Saanich_dialect#Writing_system|Ⱥ}} || '''U+023A LATIN CAPITAL LETTER A WITH STROKE || The strikethrough the letter A resembles the diagonal stroke of a capital "Z"
|}

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Language]]
[[Category:Cryptography]]
[[Category:Unicode]]
[[Category:Smartphones]]

3047: Rotary Tool

2025-02-06T14:56:16Z

172.70.91.181: /* Explanation */

{{comic
| number = 3047
| date = February 5, 2025
| title = Rotary Tool
| image = rotary_tool_2x.png
| imagesize = 528x468px
| noexpand = true
| titletext = It was great until my thumb slipped and I accidentally launched my telescope into the air at Mach 8.
}}

==Explanation==
{{incomplete|Created by AN ILLUSION THAT HELPS THINGS MAKE SENSE. Do NOT delete this tag too soon.}}

It is common to find multipurpose handheld tools that can function as higher-speed drills and lower-speed screwdrivers, switching between modes with a slider. The tool in this comic appears to have extended that concept to the extreme, covering both very high-speed and very low-speed tools. Presumably the tool has a rotating part at one end that can accept multiple attachments to facilitate the different uses.

All of these speeds are sensible for the specified uses. However, engineering a single tool to perform reliably across the required range of speeds is likely to be deeply impractical. Equally, designing the base unit such that it can be usefully employed to all these purposes would be a substantial challenge. For example, a household drill needs to be both portable and reasonably bulky, whereas a record player needs good stability, and a dental drill needs to be small enough to moved flexibly and delicately. In any case, it's highly unlikely that any individual would have a need for all these uses, so the market for such a tool would be extremely limited.

The title text highlights one of the downsides of combining functions in this way — the potential for using the wrong setting for the task at hand, by carelessness or clumsiness, with detrimental effects. In this case, while attempting to use the "sidereal telescope mount" option with an actual telescope, the user accidentally changed the tool to a much higher speed setting, launching it into the air at a {{w|hypersonic speed}}. More commonly, attempting to insert a screw while on the drill setting could cause damage to the item being screwed together, the screw itself, or the screwdriver bit.

The speed of the dental drill might seem excessive, but according to [https://sableindustriesinc.com/what-is-a-high-speed-handpiece-how-it-works-speed-more/ Sable Industries], a manufacturer of high-speed dental drills, they can run "at speeds of between 300,000 and 450,000 RPM." They squirt water as they rotate to cool the bits down, so they don't overheat (a further design complication for this multitool).

The precession setting refers to the {{w|precession of the equinoxes}}, which happens on a 26,000-year cycle that corresponds to the RPM rate shown. The average person does not need to adjust their telescope for such minor shifts, certainly not on a constant basis.{{cn}} This may be beneficial for scientists making precise measurements but they would have more powerful and dedicated tools to this end. For commercial use by the public, this would not be remotely necessary.

The speeds labeled "record player" are intended to correspond to standard rotational speeds of {{w|Phonograph record|phonograph records}}. The intended playback speed standardized at 78 rpm (not 72 rpm as depicted in the comic) in the 1920s, with a diameter of 10 inches. The speed and size, as well as the required width of the groove encoding the music, dictated a playing time of about 3 1/2 minutes per side; collections of 78 rpm records were released as albums. Beginning in the late 1940s, records designed to be played back at 33 1/3 rpm (close enough to the 33 rpm in the comic) were produced, to allow longer play times (hence the LP designation, for "long play") on similar-sized records, which standardized on a 12 inch diameter. This was commonly used to release an collection of songs on a single disc (still called an "album"), totaling about 22 minutes per side. Concurrently, an alternate format, 7 inch diameter records designed to be played at 45 rpm, was produced, allowing about 5 minutes per side. This was often used to release "singles" (a single song on each side of the record). The 33 1/3 and 45 rpm playback speeds supplanted 78 rpm, and remain the standards today.

{| class="wikitable" style="margin:auto"
|-
! Function !! Speed (rpm) !! Revolution time !! Notes
|-
| Sidereal Mount Precession Adapter || 0.000000000073 || ~26,000 years || see [https://en.wikipedia.org/wiki/Axial_precession Axial precession]
|-
| Sidereal Telescope Mount || 0.00070 || 23.93 hours || Rotates once a [https://en.wikipedia.org/wiki/Sidereal_time sidereal day].
|-
| Hour hand on a clock || 0.0014 || 12 hours
|-
| Minute hand on a clock || 0.017 || 60 minutes
|-
| Second hand on a clock || 1 || 1 minute
|-
| 33 rpm Record Player || 33 || 1.8 seconds
|-
| 45 rpm Record Player || 45 || 1.3 seconds
|-
| 72 rpm Record Player || 72 || 0.8 seconds || Potential typo for 78 rpm
|-
| Screwdriver || 300 || 0.2 seconds
|-
| Drill ||1,500|| 40 milliseconds
|-
| Airplane Propeller ||2,500|| 24 milliseconds
|-
| Dremel || 35,000 || 1.7 milliseconds
|-
| Uranium Enrichment Centrifuge || 60,000 || 1 millisecond
|-
| Dental Drill || 300,000 || 0.2 milliseconds
|-
|}
[Note that all speeds are rounded to two significant figures, which may result in some variance from the intended result when trying to calculate revolution times from them.]

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

:Multi-function rotary tool

:[A slider on the side of a tool with various settings.]
:Speed (rpm) Function
:0.000000000073: Sidereal mount precession adapter
:0.00070: Sidereal telescope mount
:[Following three are labeled "clock hands":]
:0.0014: h
:0.017: m
:1: s
:[Following three are labeled "record player":]
:33: 33
:45: 45
:72: 72
:300: Screwdriver [Current setting]
:1500: Drill
:2500: Airplane propeller
:35 000: Dremel
:60 000: Uranium enrichment centrifuge
:300 000: Dental drill

{{comic discussion}}

[[Category:Telescopes]]

1606: Five-Day Forecast

2024-12-19T12:10:02Z

172.70.91.181: Undo revision 359899 by 172.71.210.193 (talk)

{{comic
| number = 1606
| date = November 20, 2015
| title = Five-Day Forecast
| image = five_day_forecast.png
| titletext = You know what they say--if you don't like the weather here in the Solar System, just wait five billion years.
}}

==Explanation==
{{w|Weather forecasting}} is an extremely difficult task, even if it is only for five days. In numerical models, extremely small errors in initial values double roughly every five days for variables such as temperature and wind velocity. So most {{w|Meteorology#Meteorologists|meteorologists}} provide us with only a five-day forecast.

In this comic [[Randall]] takes this to the extreme by first showing a '''Five-Day Forecast''' and then progressing to five-month, year, million, billion and finally trillion-year forecasts, leading to {{tvtropes|WeirdWeather|weather patterns that we don't regularly see.}}

Since the first weather symbol is the same in all six rows, we can assume it indicates the weather today and not tomorrow, in a trillion years, etc. It is only in the second panel of each row that time has passed per the row's label. Consequently, the last column gives the predictions for four days, four months, ..., four trillion years from today.

When moving past the five-day prediction, the forecast is just a qualified guess based on the time of year. In a month it is Christmas as shown in the second panel of the second row. Then it is January and February so snow is likely, but certainly not something that happens on all days of a winter month.

Looking at the five-year forecast, guesses are made as to what the weather will be like at the same time of year. For these first three predictions the weather symbols are all of the same three types: Sun, clouds and some kind of {{w|precipitation}}, rain or snow, with the temperature ranging from 21 to 44 °F (-6.1 to 6.6 °C) - winter temperatures.

Then we go into the far future, jumping a million years from panel to panel. But still the weather symbols stay the same. In 3 million years, however, aliens (or advanced humans) attack with energy beams from {{w|flying saucers}}. They are gone a million years later. The temperature range remains the same across the panels except that it rises to 52 °F (11 °C), a possible reference to global warming, in one panel, and while the attack is going on it rises to 275 °F (135 °C).

Once we get to the billion-year mark it actually becomes more meaningful to try to predict the "weather", because now we reach the times when the {{w|Sun}} begins to change. Although the Sun will continue to burn hydrogen for about 5 billion years yet (while in its {{w|Sun#Main sequence|main sequence|}}), it will grow in diameter as it begins to exhaust its supply of fuel. The core will contract to increase the temperature, and the outer layer will then compensate by expanding slightly. This is what is indicated in panels two and three, where the color of the Sun changes towards red as the surface becomes cooler as it expands away from the center of the Sun. The temperature will rise on Earth as indicated in the panels (105 °F = 40.5 °C and 371 °F = 188 °C). The temperature will get hot enough in about [http://phys.org/news/2015-02-sun-wont-die-billion-years.html a billion years] that the Earth's oceans will boil away.

Once it {{w|Sun#After core hydrogen exhaustion|no longer has enough hydrogen}}, the Sun will expand into a {{w|red giant}}. This should not happen until around {{w|Sun#Composition|five billion years from now}}, but in the forecast it is indicated to happen in only three. Maybe this is Randall taking liberties to show what happens during this phase, which would not fit into a four-billion-year forecast. Alternatively it just indicates how uncertain these kinds of forecasts are, or a statement that we may not know for certain that it will take five not three billion years.

In any case, the fourth panel shows the temperature at Earth's position inside the red giant Sun. The color of the panel indicates that we are inside the Sun. The temperature is 71,488,106 degrees Fahrenheit (39,715,597 degrees Celsius). The current temperature of the center of the Sun is "only" 27 million degrees Fahrenheit (15 million degrees Celsius), and although that may rise by a factor of ten during {{w|Stellar nucleosynthesis|helium fusion}}, that will only be at the very core and not out in the solar atmosphere reaching out to Earth. Here the temperature would only be of the order of thousands of degrees Fahrenheit, since the Sun's outer temperature decreases as it increases its diameter. So this panel's temperature also makes little sense. It may involve some ambiguities regarding what the forecast means; the edge of the red giant Sun is predicted to be somewhere near the current orbit of Earth, but the position of the Earth could change. The most likely prediction at the moment is for Earth to move outward, but if the planet is engulfed by the Sun, it would spiral inward, and at some point fall apart. So in some sense "here" for the forecast could become a position deep inside the Sun, where core temperatures could reach 100 million Kelvin. The temperatures shown are unreasonably precise; they probably should have only two or at most three significant figures.

The red giant phase lasts only half a million years, so a billion years after the Sun has been a red giant its outer atmosphere will definitely have disappeared, leaving only a dim, cool {{w|white dwarf}} to cool down. Given Randall's version of this time schedule, then it will have had about a billion years to cool down, but would still likely be the brightest object in the sky as seen from where the Earth once was. It is not shown in the last panel, where we just see other stars of the Galaxy. The temperature is down to that of the {{w|Cosmic microwave background|background radiation}}. Today this radiation has a temperature of 2.72548 kelvin = -270.4245 °C = -454.7641 °F. That is a few degrees F colder than what is shown in the comic, which states the temperature is -452 °F = 4.26 kelvin. This higher temperature may have been chosen to reflect that even the light from other stars would increase the actual temperature.

In the last panel with trillions of years, we jump right past the Sun's red giant phase to a panel looking much like the one after five billion years with only other stars. Over the next three trillion years the stars become fewer and fewer and dimmer and dimmer as they run out of fuel and fewer new stars form. After four trillion years the background temperature decreases one degree to -453 °F as the universe keeps expanding and the wavelength of the radiation does the same, thus decreasing its temperature.

The title text is a play on comments referring to fast-changing weather on a more ordinary human timescale, such as Mark Twain's quip, "If you don't like the weather in New England now, just wait a few minutes."

A ten-day forecast was used in [[1245: 10-Day Forecast]]. In [[1379: 4.5 Degrees]], Randall looked at the weather over long periods of time as well. in [[1643: Degrees]] he addressed Celsius vs. Fahrenheit for measuring temperature.

===Image using Celsius===

There is a different user-made version for the picture, using [[3001|Celsius]] instead of Fahrenheit, [[:File:five_day_forecast_Celsius.png|in this image link]].

==Transcript==
:[A grid with six rows of five columns, where each row is labeled to the left. For each of the 30 squares a temperature is given in Fahrenheit at the top left. The rest of the square represents the weather as in a weather forecast (or some other relevant items for the comic), mainly in bright colors. Below are the six labels given above each of their five weather symbols with temperature given below these symbols description.]

:'''Your 5-day forecast'''
:[A bright yellow sun.]
:38°F
:[A grey cloud.]
:41°F
:[A grey cloud with six lines of blue raindrops below.]
:36°F
:[A grey cloud in front of a yellow sun.]
:40°F
:[A bright yellow sun.]
:44°F

:'''Your 5-month forecast'''
:[A bright yellow sun.]
:38°F
:[A green Christmas tree with red presents beneath it.]
:29°F
:[A grey cloud with four snowflakes below.]
:21°F
:[A grey cloud with four snowflakes below.]
:24°F
:[A grey cloud.]
:35°F

:'''Your 5-year forecast'''
:[A bright yellow sun.]
:38°F
:[A grey cloud.]
:25°F
:[A bright yellow sun.]
:36°F
:[A grey cloud with six lines of blue raindrops below.]
:37°F
:[A bright yellow sun.]
:41°F

:'''Your 5-million-year forecast'''
:[A bright yellow sun.]
:38°F
:[A bright yellow sun.]
:52°F
:[A grey cloud.]
:40°F
:[Two red flying saucers (with bright domes) are shooting energy beams downwards. One of the beams seems to impact with something at the bottom of the panel, which then explodes. Two plumes of smoke rises up from below, drifting to the right.]
:275°F
:[A grey cloud in front of a yellow sun.]
:40°F

:'''Your 5-billion-year forecast'''
:[A bright yellow sun.]
:38°F
:[A larger orange sun.]
:105°F
:[A very large red sun.]
:371°F
:[A pale yellow panel with no drawing.]
:71,488,106°F
:[A night sky with many bright stars.]
:-452°F

:'''Your 5-trillion-year forecast'''
:[A bright yellow sun.]
:38°F
:[A night sky with many bright stars.]
:-452°F
:[A night sky with many stars.]
:-452°F
:[A night sky with fewer not so bright stars.]
:-452°F
:[A night sky with few dim stars.]
:-453°F

{{comic discussion}}

[[Category:Comics with inverted brightness]]
[[Category:Comics with color]]
[[Category:Science]]
[[Category:Space]]
[[Category:Astronomy]]
[[Category:Weather]]
[[Category:Aliens]]

Talk:3019: Advent Calendar Advent Calendar

2024-12-03T10:56:06Z

172.70.91.181:

Would this basically be triangle numbers? So on Christmas Eve you would open 300 windows?[[User:Tommyds|Tommyds]] ([[User talk:Tommyds|talk]]) 16:01, 2 December 2024 (UTC)
:Yes and no. It's not 12 days of Christmas (as mentioned in the title text), so only the overall number of gifts are a triangle number; you open 30 windows on Christmas Day. The 12 days ref is key as the song generates more gifts if taken literally even in 12 days -- 78 on the last day, 66 on the previous day, etc, for a total of 364. [[User:Mneme|Mneme]] ([[User talk:Mneme|talk]]) 16:35, 2 December 2024 (UTC)

Notice that this year The Advent calendars are correct. Normally, Advent calendars start at the 1st of December even if the Advent starts at a different day. But this year the Advent also starts at the 1st of December. [[Special:Contributions/162.158.172.40|162.158.172.40]] 16:55, 2 December 2024 (UTC)

Donald Knuth wrote a paper for April 1984 Communications of the ACM that included an analysis of the complexity of 12 Days of Christmas. It's in the CACM archive https://dl.acm.org/doi/pdf/10.1145/358027.358042. {{unsigned ip|172.70.211.144|16:58, 2 December 2024 (UTC)}}

The explanation currently says "each day, he gets another advent calendar, which each contains 24-25 different items". I don't think that's correct; look at the picture: each day's calendar has one fewer item than the previous one. For example, the 24th only has 2 boxes and the 25th only has one. --[[User:Itub|Itub]] ([[User talk:Itub|talk]]) 17:25, 2 December 2024 (UTC)

Perhaps each smaller advent calendar might also contain a smaller advent calendar and so on ...? [[Special:Contributions/172.70.90.199|172.70.90.199]] 17:51, 2 December 2024 (UTC)
:Since the 1st has a calendar with a 1st, that would mean an infinite number of calendars just on the first day, so probably not. [[Special:Contributions/172.71.154.225|172.71.154.225]] 18:03, 2 December 2024 (UTC)
::It could work out if you don't open the first window of a new advent calendar on the day that it is revealed. So on day 1, you open the first window revealing an advent calendar that starts on day 2. Then on day 2 you open the second window, revealing a second advent calendar and the first window of the day 1 advent calendar, revealing a third advent calendar. ... and so on. If my mental math on that is right, it's doubling every day, so 2^24 =~ 16M calendars in total? (I could be off by a day) [[Special:Contributions/172.71.147.69|172.71.147.69]] 19:38, 2 December 2024 (UTC)

Can we just take a moment to appreciate whoever named the bot for this page? They wrote as follows: Created by 4 ENVELOPE BACKS 3 NERDS A-EDITING, 2 TURTLE BOTS, AND A FUNNY NEW XKCD. [[User:Willintendo|Willintendo]] ([[User talk:Willintendo|talk]]) 23:26, 2 December 2024 (UTC)
:That note is hand-edited on the first couple of edits. Not sure why that rule exists, though. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 00:50, 3 December 2024 (UTC)

The title text says 'may' twice, "per day may may [sic] seem absurd" --[[Special:Contributions/198.41.236.163|198.41.236.163]] 00:01, 3 December 2024 (UTC)

The German YouTube channel "Malternativ" has actually done this a couple years: Opening one advent calendar every day. He went more and more insane as December went on… [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 00:50, 3 December 2024 (UTC)

Noting that the calendar is entirely correct for the day of publication. Too much to hope for that it is ''kept'' correct for each further day of Advent until (or, rather, 'until and including', as noted at least once above) Christmas Day? Maybe worth checking to see if (at an appropriate time, Randall-time, later today on the 3rd) it hasn't been updated. Or some special sub-page appeared with a revised (Time-like) update. Just in case. And, if Randall doesn't, I'm sure it's not beyond our own wit to make adjustments/animate as a fan-copy. [[Special:Contributions/172.70.91.214|172.70.91.214]] 01:57, 3 December 2024 (UTC)

[https://knowyourmeme.com/memes/xzibit-yo-dawg Yo Dawg], I herd you like advent calendars, so I put an advent calendar in your advent calendar so you can count down while you count down. [[User:Solomon|Solomon]] ([[User talk:Solomon|talk]]) 03:31, 3 December 2024 (UTC)

Wonder how many chocolates you would get if you did this with the life expectancy advent calendar. [[User:N-eh|N-eh]] ([[User talk:N-eh|talk]]) 04:40, 3 December 2024 (UTC)
:At some point, most people would reach the point at which that many chocolates would be a lethal (or at least LD50) quantity, so would be a self-shortening process. For those who reach the end of their LEAC ''without'' it actually being the cause of death, there should be a compensatory (or 'condolances') supply hidden on the back, for entirely guilt-free eating. [[Special:Contributions/172.70.162.200|172.70.162.200]] 06:01, 3 December 2024 (UTC)

Nobody tell Stuart and Dan about this one... [[Special:Contributions/172.71.183.11|172.71.183.11]] 06:56, 3 December 2024 (UTC)

I still don't understand it. Does he not open the first and second door of the second calendar on the second day? If not, does he open the first or the second door of the second calendar. Do the other items stay in the calendar? [[Special:Contributions/162.158.245.162|162.158.245.162]] 07:36, 3 December 2024 (UTC)
:Each next calendar has one fewer doors. So the second calendar starts with door number 2. On 1 December he opens the number 1 door revealing the first subcalendar, where he opens the number 1 door. On 2 December he opens the number 2 door of the first subcalendar and then the second door of the big calendar, revealing the second subcalendar, where he opens the first door, which is the number 2 door, since it has no number 1 door. [[User:Mtcv|Mtcv]] ([[User talk:Mtcv|talk]]) 08:12, 3 December 2024 (UTC)

Is the title correct, from a formal language point of view? I would have expected it to be Advent Advent Calendar. OTOH I'm not American and not overtly familiar with this tradition.

3014: Arizona Chess

2024-11-20T15:39:58Z

172.70.91.181: /* Explanation */

{{comic
| number = 3014
| date = November 20, 2024
| title = Arizona Chess
| image = arizona_chess_2x.png
| imagesize = 740x315px
| noexpand = true
| titletext = Sometimes, you have to sacrifice pieces to gain the advantage. Sometimes, to advance ... you have to fall back.
}}

==Explanation==
{{incomplete|Created by a DAYLIGHT SLAYING BOT - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

[[White Hat]] and [[Cueball]] are playing a game of chess, perhaps at a championship. White Hat is in the advantage, as he has one more pawn than Cueball and has more time on the {{w|chess clock|clock}}. However, Cueball has an unexpected advantage. The building is sited across the border of Arizona with another state, with White Hat on the Arizona side, and the game is being played at a very particular time of year. As Arizona doesn't do {{w|daylight saving time}}, unlike neighboring US states, only one clock gains an hour. White Hat's time remains normal, but Cueball's time "falls back" one hour, as his departure from daylight saving time occurs. Due to the way the timer apparently calibrates its display (perhaps in part based upon something like the self-adjusting [https://en.cppreference.com/w/c/chrono/localtime localtime()] function), Cueball is suddenly given more time in the game.

White Hat, whose timer instance is governed by a different locale, protests as this is not typically how these clocks should function.

The title text is a pun with the idea of "falling back" strategically from an attack and the term "fall back" in the mnemonic used to remember which way the clock changes when we go in and out of DST: "spring forward, fall back" (we advance the clock forward when entering DST in the spring, and move it backward when leaving it in the fall).

Hawaii also doesn't observe DST but, since it is an achipelago, it doesn't share a land border with any other state, so a game like this is not possible.

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

:[White Hat and Cueball are sitting across from each other playing chess. The time, shown above them in white on a black screen, reads 6:35 for White Hat, and 0:28 for Cueball.]
:White Hat: It’s late, I’m up a pawn, and you’re out of time. It’s over.
:Cueball: Ah, you’re forgetting something.

:[Cueball gestures with one hand above the chessboard. His time now reads 0:19.]
:Cueball: Did you know this building straddles the Arizona border?
:Cueball: It actually runs right through the table. You're on the Arizona side.

:[Cueball raises his hand further to gesture at his time. It beeps and is now blank and white.]
:Cueball: This tournament started Saturday, November 2nd. Now it's almost 2AM on the 3rd.
:Cueball: And there's something you should know about Arizona.
:Chess clock: BEEP

:[White Hat raises his head slightly to look at the timer. Cueball's time now reads 60:07.]
:White Hat: '''''What?!''''' No! That's not how... '''''No!!'''''
:Cueball: Looks like it's daylight '''''slaying''''' time.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Chess]]
[[Category:Daylight saving time]]

Talk:3013: Kedging Cannon

2024-11-19T09:46:27Z

172.70.91.181:

First? [[User:PRR|PRR]] ([[User talk:PRR|talk]]) 02:05, 19 November 2024 (UTC)

Good essay on real-life (or this-world) kedging-- http://www.sailmagazine.com/cruising/cruising-tips/the-lost-art-of-kedging-how-to-set-a-kedge-anchor/ [[User:PRR|PRR]] ([[User talk:PRR|talk]]) 02:07, 19 November 2024 (UTC)

:Nice. I think I managed to somehow get in first (before I logged in); first time I've done so, so apologies for not knowing all the conventions. I think the title text is the main non-obvious thing, since the simile between a windmill's mechanical function and that of tacking seems clearly intentional,but I'm sure that could be edited to be clearer than my hasty writup. [[User:Mneme|Mneme]] ([[User talk:Mneme|talk]]) 02:10, 19 November 2024 (UTC)

For a brief, brief, moment, my brain failed to swap in and dredge up the memory of what kedging was, and I wondered if they were trying to use the aft cannon as a weak propulsion mechanism (hey, if it was a spacecraft…). And then I remembered what kedigng was and—DUH! [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 02:29, 19 November 2024 (UTC)

If it wasn't for kedging, I probably wouldn't be able to make it all the way through November. [[Special:Contributions/108.162.245.133|108.162.245.133]] 04:25, 19 November 2024 (UTC)

Wow, whoever wrote the Speed and Economic Analysis section, you are amazing! [[Special:Contributions/172.71.98.135|172.71.98.135]] 05:13, 19 November 2024 (UTC)