explain xkcd - User contributions [en]

Talk:3045: AlphaMove

2025-02-02T17:41:52Z

141.101.76.164:

Ask Tom Murphy VII to get on this [[Special:Contributions/141.101.99.103|141.101.99.103]] 22:50, 31 January 2025 (UTC)

This has actually been done and tested against other strange algorithms:
https://youtu.be/DpXy041BIlA?t=729

I have attempted to run the proposed bot against itself — if I haven't made any errors, here are the resulting games:

Rounding down:
1. e4 e6 2. f3 f5 3. e5 g5 4. d4 d5 5. exd6 g4 6. d7+ Kf7 7. dxc8=N Ke8 8. fxg4 h6 9. gxf5 Kd7 10. g4 h5 11. fxe6+ Ke8 12. g5 Na6 13. h3 Nc5 14. h4 Ne7 15. Kd2 Ne4+ 16. Ke1 Nf5 17. g6 Nf6 18. g7 Ng3 19. gxf8=N Nge4 20. Ke2 Ng4 21. Kf3 Ngf2 22. Ke2 Nh3 23. Ke3 Nhf2 24. Nb6 Nh3 25. Na4 Nhf2 26. Nac3 Nxc3 27. Kxf2 Nxd1+ 28. Kf3 Qc8 29. c4 Ne3 30. Ke4 Nf5 31. Kd3 Ng3 32. e7 Nxh1 33. Kc2 Qb8 34. d5 Kxe7 35. d6+ Kf6 36. dxc7 Nf2 37. c8=R Ng4 38. Kd2 Nh2 39. Ke3 Ng4+ 40. Kd4 Nh2 41. Kd5 Nxf1 42. Nc3 Nh2 43. Nce2 Ng4 44. Nd4 Nh6 45. Nd7+ Kf7 46. Ndf3 Qd6+ 47. Ke4 Qd2 48. Nf8 Qd5+ 49. Ke3 Qd2+ 50. Ke4 Qd5+ 51. Ke3 Qd2+ 52. Ke4

Rounding up:
1. f3 f5 2. e4 f4 3. d4 e6 4. e5 g6 5. g3 fxg3 6. c3 g2 7. d5 gxf1=Q+ 8. Kxf1 exd5 9. Ke2 d6 10. Kd3 g5 11. Kd2 dxe5 12. Ke2 d4 13. Kd3 dxc3+ 14. Ke3 e4 15. Ne2 exf3 16. Ng1 f2 17. Nxc3 fxg1=N 18. Qc2 Kd7 19. Ne2 h6 20. Qa4+ Ke6 21. Qb3+ Ke7 22. Qb4+ Ke8 23. Qb5+ Kf7 24. Qa6 Kg7 25. Qa4 Kg6 26. Qb3 Kg7 27. Qb4 Kh7 28. Qb5 Kg7 29. Qa6 Nc6 30. Nxg1 Na5 31. Qb6 Kh7 32. Qb3 Kg6 33. Qb4 Kg7 34. Qb6 Kh7 35. Qb3 Kg6 36. Qb4 Kg7 37. Qb6

Rounding down code:
const { Chess } = require("chess.js");

const chess = new Chess();
while (!chess.isGameOver()) {
const moves = chess.moves();
moves.sort((a, b) => b.localeCompare(a));
const move = moves[Math.floor(moves.length / 2)];
chess.move(move);
}
console.log(chess.pgn());

To round up, swap the a and b in the sort function.

Both games end in a threefold repetition draw. The game with rounding down does, in fact, have 6 knights in it, so I believe he did code this to see what would happen.

[[User:Ohpointfive|Ohpointfive]] ([[User talk:Ohpointfive|talk]]) 22:52, 31 January 2025 (UTC)

To elaborate on the Tom VII point - this is the YouTube video that possibly inspired the comic: https://www.youtube.com/watch?v=DpXy041BIlA

[[Special:Contributions/141.101.98.179|141.101.98.179]] 22:55, 31 January 2025 (UTC)
:Specifically, it's the [https://www.youtube.com/watch?v=DpXy041BIlA&t=1483 Arithmetic Player at 24:43] set to ½. [[User:ChaoticNeutralCzech|ChaoticNeutralCzech]] ([[User talk:ChaoticNeutralCzech|talk]]) 17:52, 1 February 2025 (UTC)

Unfortunately for white, it's mate in 1 with Bb4# [[Special:Contributions/162.158.90.124|162.158.90.124]] 23:25, 31 January 2025 (UTC)

Even if white makes a different move, its still forced mate in one. RIP XKCD Bot. [[User:Redacted II|Redacted II]] ([[User talk:Redacted II|talk]]) 00:53, 1 February 2025 (UTC)
:Well, for most options. Queen to a4 puts Black in check, forestalling an immediate move to mate White; capturing the knight de-threatens enough squares around the king that Black can't check next turn without leaving an escape route. [[Special:Contributions/172.70.176.28|172.70.176.28]] 17:45, 1 February 2025 (UTC)

<s>Although it wouldn't change the outcome much (either by changing black's move or white's general options), I'm currently not understanding why Kd4 isn't on the list of options at this point in time. So long since I played serious(ish) chess, and the only reason I could think of is that it's probibited by some strict ortbodox game rule recognising the ''potential'' moving of the knight out of the way (in the next white move-cycle). But I'd have treated that later option as forbidden, as a revealing-mate. But, as I said, it's been a while, so maybe I'm just blind to something like a sweeping bishop-range that disbars this (much as the near knight, bishop and pawn disbars four out of the five moves).</s> ...darn, it's just clicked. That's the AlphaMoved white-knight's destination (before that, the black queen was entirely covering that square, and double-teaming one of the adjacent black-knight covered squares), I'd been thinking that was the piece's origin (with the empty highlighted square as its destination) until I'd finally read the highlighted movelist item properly and deciphered it as Knight To King Two (done), not the (intention of) Knight To King's Bishop One. So ignore the above. Although, just to note, for the Black Queen to have even achieved that position would probably have required at least ''one'' normally-sacrificial exposure to the deadly white Q/B/R pieces guarding the obvious entry, give or take the algorithmic development of their (and the "gateway pawns"') current positions. [[Special:Contributions/141.101.99.104|141.101.99.104]] 02:00, 1 February 2025 (UTC)
:Follow-up... As far as the black queen is concerned, I suppose she could have done d6, (x?)g3 then f2, in-between the other black and white moves made, largely safe from the white 'defence'. Or to d4 then f2, if white Queen's Pawn was shielding still. (Appears to have been taken, but it would have been bold to have done that with the queen, for a normally immediate pawn-queen exhange!) A bolder/more opportunistic set of moves than I would have tried, either. Even (unknowingly) against AlphaMove, I'd have been wary of the unconventionally developing white disposition actually being an idiot-trap (and I'm really not that far off being an idiot, insofar as chess). [[Special:Contributions/172.70.162.162|172.70.162.162]] 02:17, 1 February 2025 (UTC)

The explanation gives both O-O and 0-0 as notations for castling and then explains why 0-0 can never occur, even though O-O can be sorted pretty centrally. So, which is the correct notation? [[Special:Contributions/172.71.250.91|172.71.250.91]] 09:14, 1 February 2025 (UTC)
:According to the [https://ia802908.us.archive.org/26/items/pgn-standard-1994-03-12/PGN_standard_1994-03-12.txt pgn spec], section 8.2.3.3: they are capital Os and not zeros [[Special:Contributions/172.68.3.96|172.68.3.96]] 15:10, 1 February 2025 (UTC)

I'm pretty sure we're looking at a retrograde puzzle. [[User:Ohpointfive|Ohpointfive]] is onto something here, with the six knights on the board a strong indicator. The question is, of course, where is the joke? White plays Alphamove all along and must have started with e4 (rounding down) or f3 (rounding up). Both are consistent with the end position. So from my point of view, the joke is
* either that the "stronger engine" is not a strong engine at all but maybe the same algorithm, rounding up instead of down
* or that black doesn't win this position (in real chess, White is of course toast) because its algorithm is even worse
@Ohpointfive, could you run the two versions against each other? --[[User:Pganon|Pganon]] ([[User talk:Pganon|talk]]) 15:55, 1 February 2025 (UTC)

I created a playable version of this game in like 10 minutes using ChatGPT ;)

https://enn-nafnlaus.github.io/AlphaMove/alphamove.html

Git page here:

https://github.com/enn-nafnlaus/AlphaMove

-- [[User:Rei|Rei]] 17:52, 1 February 2025 (UTC)

I checked, castling and en passant both work. [[Special:Contributions/172.68.245.25|172.68.245.25]] 19:26, 1 February 2025 (UTC)

@Pganon certainly:
White rounding down vs. black rounding up:
1. e4 f5 2. f3 f4 3. d4 e6 4. e5 g6 5. d5 exd5 6. g3 fxg3 7. c4 g2 8. h3 gxf1=Q+ 9. Kd2 Kf7 10. Kc3 Ke8 11. Kc2 Kf7 12. Kb3 Ke8 13. Kc2 Kf7 14. Kb3 Ke8 15. Kc2
White rounding up vs. black rounding down:
1. f3 e6 2. e4 f5 3. e5 g5 4. d4 d5 5. f4 gxf4 6. h3 h5 7. h4 Kd7 8. Kd2 Kc6 9. Kd3 Kb6 10. Ke2 Kb5 11. Ke1+ Kb4 12. Ke2 Kb5 13. Ke1+ Kb4 14. Ke2 Kb5

The first game is quite exciting, with black at one point having a chance at checkmate in one, but alas too many available pawn moves drives the winning move Qxc4# far past the center of the list. The second game is much less exciting.

[[User:Ohpointfive|Ohpointfive]] ([[User talk:Ohpointfive|talk]]) 21:30, 1 February 2025 (UTC)

Here's a question: What is the quickest way to checkmate AlphaMove? Here's the quickest that I have found so far:
# f3 d5
# e4 d5xe4
# f4 e5
# g3 Bg4
# d4 Qxd4
# f5 e3
# f6 Qxd1#
Thus, we have mate in seven. This might be good to mention outside the comments section as a demonstration tha AlphaGo is not very good (not to mention failing to attack black's queen with a less valuable piece), but a quicker checkmate might be possible, in which case we should mention that instead.[[Special:Contributions/172.70.207.159|172.70.207.159]] 11:08, 2 February 2025 (UTC)

: Checkmating Alphamove is easy. Getting checkmated *by* Alphamove is challenging. You basically have to forget everything you know about normal chess. -- [[User:Rei|Rei]] ([[User talk:Rei|talk]]) 14:48, 2 February 2025 (UTC)

One possible move, Kd2, is missing! /[[Special:Contributions/141.101.76.164|141.101.76.164]] 17:41, 2 February 2025 (UTC)

3014: Arizona Chess

2024-11-21T21:05:38Z

141.101.76.164: /* Explanation */ clarification

{{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 timed game of tournament-style chess. At the start of the comic White Hat has the advantage because, as well as having one more pawn than Cueball, he has more time left to play his remaining moves — 6 minutes and 35 seconds, versus Cueball's 28 seconds, as shown on the {{w|chess clock}} display above them.

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, when (most of) the United States exits {{w|Daylight Saving Time}}, which happens at 2:00 AM on the morning of the first Sunday in November. As Arizona doesn't observe Daylight Saving Time (DST), 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, giving him 60 additional minutes of play time. White Hat immediately protests, likely trying to communicate that such is not how chess clocks work. Chess clocks are simple timers, tracking how much time each player has used since the beginning of the match. They're not based on local time, and changing the time remaining during play would certainly be a violation of the rules. Even clocks that do track local time are generally not so carefully calibrated that they would reliably switch times so close to a state line.

Cueball ignores these protests, and now seems confident of victory, since he has far more play time remaining. Daylight Slaying Time is a pun on Daylight Saving Time, but note that the comic takes place as the non-Arizona clock stops observing DST and joins the Arizona clock in Standard Time.

The title text makes use of a pun. To "fall back" in a strategic sense means to withdraw from an attack, or even to retreat. This can be part of a valid strategy, as withdrawing from an engagement can allow you to press the attack elsewhere, at a more advantageous time and place, or can draw enemy forces into an attack under circumstances that you control. [https://www.timeanddate.com/time/dst/spring-forward-fall-back.html "Spring forward, fall back"] is a mnemonic used for daylight saving time; we advance the clock forward when entering DST in the spring, and move it backward when leaving it in the fall (autumn).

There are buildings in the US that are built across state lines (and county and city boundaries), and even some buildings that extend across international boundaries (these are known as {{w|line house}}s). The existence of these buildings can result in eccentric situations when laws and ordinances vary substantially between the locations. For example, a casino might be built on a state border where gambling is legal in one state but illegal in the other. In such a case, the gaming can only happen on one side of the building (the other side being reserved for other services and functions). It's not uncommon for businesses and tourist attractions to lean into the novelty of this by demarking the boundary inside the building and specifically encouraging things that are legal only on one side of the line. Such situations are likely the inspiration for this strip, but using such a line to manipulate a competition based on time zone is highly unlikely.

Ongoing state-level efforts to end time changes could also increase the number of places where this situation could happen, as more DST/non-DST boundaries arise.

The comic was published five days before the start of the {{w|World Chess Championship 2024}} in Singapore.

==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. Cueball lowers his hand to make a move.]
: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:1366: Train

2023-08-09T06:30:38Z

141.101.76.164: Comment

I just did an explanation from scratch for the first time, please could you tell me how I could improve it? Thanks :) [[User:Cheeselord99|Cheeselord99]] ([[User talk:Cheeselord99|talk]]) 07:02, 9 May 2014 (UTC)

Am I the only one who gets [[Inflation]] when going to xkcd.com (without the www)? This comic shows at www.xkcd.com and m.xkcd.com however. [[Special:Contributions/108.162.221.5|108.162.221.5]] 07:11, 9 May 2014 (UTC)

:I created an account. The 108.162.221.5 ip address today is me, along with 108.162.221.53 today. [[User:Mikemk|Mikemk]] ([[User talk:Mikemk|talk]]) 07:16, 9 May 2014 (UTC)
:I thought today's comic was late. http://www.xkcd.com/1366/ kept on displaying "Web-page not available" (browser thing, not server-thing), then I checked here. So. Oh, http://www.xkcd.com/ also... Hmmm... That's not right. Oh, "Ping request could not find host www.xkcd.com. Please check the name and try again." DNS errors? Only those trying via cached details get anything? Things are not working for xkcd.com or m.xkcd.com either. So, DNS poisoning or human error of some kind? Not the place to discuss this, I know, sorry... [[Special:Contributions/141.101.89.211|141.101.89.211]] 10:05, 9 May 2014 (UTC)

:Explanation is good, but there are certainly related comics or maybe what-if ... I've found [http://what-if.xkcd.com/58/ Orbital Speed], but I think there were something mentioning how fast sun goes relatively to galaxy ... -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:14, 9 May 2014 (UTC)
::Found two related comics - any other? [[User:Condor70|Condor70]] ([[User talk:Condor70|talk]]) 11:33, 9 May 2014 (UTC)

It sounds like the dark matter engine in Futurama:http://futurama.wikia.com/wiki/Dark_matter_engine {{unsigned ip|108.162.215.77}}
:That's just what I was thinking! --[[Special:Contributions/173.245.55.66|173.245.55.66]] 17:53, 12 May 2014 (UTC)
I think the last paragraph, considering the situation from the point of view of multiple trains, is not relevant. The whole concept of what makes this idea funny and interesting is that you MUST view the situation from the point of view of a single train (or elevator). --[[User:RenniePet|RenniePet]] ([[User talk:RenniePet|talk]]) 13:24, 9 May 2014 (UTC)
: Second-last paragraph - my comment was written at the same time as another paragraph was added. --[[User:RenniePet|RenniePet]] ([[User talk:RenniePet|talk]]) 13:26, 9 May 2014 (UTC)

I do not understand what the last paragraph is suggesting as it seems to violate the 3rd Newtonian law of motion.

The last paragraph is not correct, the Earth would also experience an acceleration (albeit a small one).--[[User:Sturmonium|Sturmonium]] ([[User talk:Sturmonium|talk]]) 13:54, 9 May 2014 (UTC)

This line:
"The logic of the comic also fails when taking acceleration into account. Whether the train or earth is moving can be determined by which one experiences a force due to acceleration or deacceleration when the train starts."
is incorrect, according to the principle of General Relativity. You cannot experimentally distinguish between your own acceleration against a fixed universe, and your position remaining fixed against an accelerating universe. This applies for rotation as well; if you fix the reference frame of the train rider, the acceleration of the universe creates gravity waves that cause any rider on the train to experience what feels like an acceleration. Therefore, the logic of the comic is indeed correct, even for accelerating trains. I will correct this edit.--[[User:JB Gnome|JB Gnome]] ([[User talk:JB Gnome|talk]]) 14:12, 9 May 2014 (UTC)
: But the comic doesn't say that the train accelerates the universe: rather, it just accelerates the Earth. Does that make a difference? [[Special:Contributions/141.101.89.225|141.101.89.225]] 14:34, 9 May 2014 (UTC)

Does anyone have an idea where "train guy" is heading? He's saying "almost", like he's almost there but wasn't sure if there was something more. Maybe he's timing when he needs to jump off the train? [[Special:Contributions/173.245.55.62|173.245.55.62]] 14:58, 9 May 2014 (UTC)Pat

I see this comic as a nice ab absurdo for the many people who think the sun rotates around us, and further to those who claim the earth has 6 thousand years etc... [[Special:Contributions/108.162.242.117|108.162.242.117]] 18:12, 9 May 2014 (UTC)

I don't have a citation, but some traditional Polynesian navigation works using this view. Their "maps" are made of a grid of bush materials where intersections are stars or islands (possibly with a pebble tied on to represent the island). They consider the map and the earth to be connected, and you don't move along the map - the map moves. So you don't go to another island, you bring it to you. At night you move the stars to the right place, and during the day you paddle the sea and land so they are in the right place and direction.--[[User:DivePeak|DivePeak]] ([[User talk:DivePeak|talk]]) 21:15, 9 May 2014 (UTC)

A train rotating the Earth is NOT physically equivalent to a train traversing the Earth. It would be true for a flat Earth, but rotation is absolute, see Newton's bucket argument. [http://en.wikipedia.org/wiki/Bucket_argument] --[[User:Gleyshon|Gleyshon]]

I am only a layperson, but as i read it the explanation confuses coordinate systems for the description of motion with physical explanation. The reasons why the train cannot be seen as accelerating the earth/universe are so numerous (even ignoring the other objects moving in different ways) it's just for subjective fun that i'll point out a few: The rest mass of the earth is not relative, so neither is the force needed to accelerate it -- force which the train cannot create by a factor of kajillions (roughly ;^). And if it did, the area would turn into plasma. Sticking to the comic, there isn't enough friction/rigidity/etc for the wheels/rails to "grab the earth". (Notice these are local observations unaffected by any relativity.) If somehow the earth could be accelerated in this manner, the rest of the universe wouldn't go along with it. And if it did, astronomical objects wouldn't change apparent position until their light reached us. Finally, rotation of massive bodies creates {{w|Frame-dragging}} (the twisting of spacetime) which is locally observable. So: the point of the comic isn't that the view presented is counter-intuitively valid (with awkward math); rather the comic is funny because of how badly this view fails. But i don't think i'm the person to rewrite the explanation... [[User:Noobgeek|Noobgeek]] ([[User talk:Noobgeek|talk]]) 16:59, 15 May 2014 (UTC)
:That physics are easy to understand:
:*At the train you just see the Earth is moving.
:*On Earth surface you just see that the train is moving.
:Just get into the train without any knowledge about the size or mass of the Earth, and you just see the surface beyond you is moving. I will try to enhance the explain on this matter. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:39, 15 May 2014 (UTC)
::Hi there! You're right that you can often exclude information and be left with various "relativities". But (to give only one argument) the comic explicitly describes the entire planet being grabbed and rotated to a new orientation. Mountains and all :^) [[User:Noobgeek|Noobgeek]] ([[User talk:Noobgeek|talk]]) 15:07, 16 May 2014 (UTC)

It's fun to play with the physics, but the explanation is just wrong re the comic expressing a valid perspective in physics, most directly for the reason supplied by the title text: Multiple trains and elevators are moving relative to each other, so their mode of operation can't be to stay still and shift the earth. (The point of the title text might be to make the false-physics joke extra clear.) I'm going to rewrite the explanation if no one else does -- but this will be my first big edit, so before i do, to be a polite noob, i'm requesting objections. [[User:Noobgeek|Noobgeek]] ([[User talk:Noobgeek|talk]]) 19:58, 23 May 2014 (UTC)

hey cool, i live in oxford [[User:Beanie|Beanie]] [[User talk:Beanie|talk]] 11:24, 1 July 2021 (UTC)

Having read this proposed explanation and those of other comics, it seems that a lot of them (including this one) appear to omit explaining their humour, which is very often derived from their completely absurd propositions. Other commenters have alluded to this too. Lay people don't understand physics to this depth, or physics may appear boring to them due to their ignorance of it. But it doesn't follow that Randall, being an expert in physics, is either boring or doesn't have a sense of humour. Shouldn't these comic strip explanations attempt to explain the ''absurdity'' of their proposals first as opposed to the physics of them? That way, we get to know Randall's wit a little better and can better appreciate his past and future work. This comic strip, to me, represents a very novel take on the classic ''Tail wagging the Dog'' scenario and I came to this wiki hoping to get a bit more insight into Randall's interest in these kind of scenarios. I have been disappointed, but I hope that might change. [[Special:Contributions/141.101.76.164|141.101.76.164]] 06:30, 9 August 2023 (UTC)