explain xkcd - User contributions [en]

3054: Scream Cipher

2025-02-21T19:00:07Z

172.69.246.150:

{{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 - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
A {{w|substitution cipher}} is a simple form of encryption where each letter in the original text is replaced with a unique letter. In the comic's cipher, the replacement letters are all variants of the letter A with different {{w|diacritical marks}}.

It's named "Scream Cipher" (as a pun on stream ciphers, 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 is not a reference to IBM's {{w|Scream_(cipher)|Scream cipher}} published in 2002.

In the comic, [[Cueball]] texts the cipher for "HELLO", and [[Megan]] responds with the cipher for "HI".

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

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

Unicode description of the cipher:

{|class="wikitable"
! Input !! colspan=2 | Substitution
|-
| U+0041 LATIN CAPITAL LETTER A || A || '''U+0041 LATIN CAPITAL LETTER A
|-
| U+0042 LATIN CAPITAL LETTER B || Ȧ || '''U+0226 LATIN CAPITAL LETTER A WITH DOT ABOVE
|-
| U+0043 LATIN CAPITAL LETTER C || A̧ || U+0041 LATIN CAPITAL LETTER A, U+0327 COMBINING CEDILLA
|-
| U+0044 LATIN CAPITAL LETTER D || A̲ || U+0041 LATIN CAPITAL LETTER A, U+0332 COMBINING LOW LINE
|-
| U+0045 LATIN CAPITAL LETTER E || Á || '''U+00C1 LATIN CAPITAL LETTER A WITH ACUTE
|-
| U+0046 LATIN CAPITAL LETTER F || A̮ || U+0041 LATIN CAPITAL LETTER A, U+032E COMBINING BREVE BELOW
|-
| U+0047 LATIN CAPITAL LETTER G || A̋ || U+0041 LATIN CAPITAL LETTER A, U+030B COMBINING DOUBLE ACUTE ACCENT
|-
| U+0048 LATIN CAPITAL LETTER H || A̰ || U+0041 LATIN CAPITAL LETTER A, U+0330 COMBINING TILDE BELOW
|-
| U+0049 LATIN CAPITAL LETTER I || Ả || '''U+1EA2 LATIN CAPITAL LETTER A WITH HOOK ABOVE
|-
| U+004A LATIN CAPITAL LETTER J || A̓ || U+0041 LATIN CAPITAL LETTER A, U+0313 COMBINING COMMA ABOVE
|-
| U+004B LATIN CAPITAL LETTER K || Ạ || '''U+1EA0 LATIN CAPITAL LETTER A WITH DOT BELOW
|-
| U+004C LATIN CAPITAL LETTER L || Ă || '''U+0102 LATIN CAPITAL LETTER A WITH BREVE
|-
| U+004D LATIN CAPITAL LETTER M || Ǎ || '''U+01CD LATIN CAPITAL LETTER A WITH CARON
|-
| U+004E LATIN CAPITAL LETTER N || Â || '''U+00C2 LATIN CAPITAL LETTER A WITH CIRCUMFLEX
|-
| U+004F LATIN CAPITAL LETTER O || Å || '''U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE
|-
| U+0050 LATIN CAPITAL LETTER P || A̯ || U+0041 LATIN CAPITAL LETTER A, U+032F COMBINING INVERTED BREVE BELOW
|-
| U+0051 LATIN CAPITAL LETTER Q || A̤ || U+0041 LATIN CAPITAL LETTER A, U+0324 COMBINING DIAERESIS BELOW
|-
| U+0052 LATIN CAPITAL LETTER R || Ȃ || '''U+0202 LATIN CAPITAL LETTER A WITH INVERTED BREVE
|-
| U+0053 LATIN CAPITAL LETTER S || Ã || '''U+00C3 LATIN CAPITAL LETTER A WITH TILDE
|-
| U+0054 LATIN CAPITAL LETTER T || Ā || '''U+0100 LATIN CAPITAL LETTER A WITH MACRON
|-
| U+0055 LATIN CAPITAL LETTER U || Ä || '''U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS
|-
| U+0056 LATIN CAPITAL LETTER V || À || '''U+00C0 LATIN CAPITAL LETTER A WITH GRAVE
|-I'll
| U+0057 LATIN CAPITAL LETTER W || Ȁ || '''U+0200 LATIN CAPITAL LETTER A WITH DOUBLE GRAVE
|-
| U+0058 LATIN CAPITAL LETTER X || A̽ || U+0041 LATIN CAPITAL LETTER A, U+033D COMBINING X ABOVE
|-
| U+0059 LATIN CAPITAL LETTER Y || A̦ || U+0041 LATIN CAPITAL LETTER A, U+0326 COMBINING COMMA BELOW
|-
| U+005A LATIN CAPITAL LETTER Z || Ⱥ || '''U+023A LATIN CAPITAL LETTER A WITH STROKE
|}

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

:[Top of the panel has 26 letters of the alphabet, each followed by a hyphen and the letter "A" with a unique diacritical mark for each:]
:{|
|A - A
|-
|B - Ȧ
|G - A̋
|L - Ă
|Q - A̤
|V - À
|-
|C - A̧
|H - A̰
|M - Ǎ
|R - Ȃ
|W - Ȁ
|-
|D - A̲
|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
|}

:[Cueball and Megan typing on their phones, Cueball with two hands and Megan with one hand.]
:Cueball's phone: A̰ÁĂĂÅ
:Megan's phone: A̰Ả

:[Caption below the panel:]
:In the ''Scream Cipher'': AAAAAA A ÃA̧AȂA̦ ǍÅÂÃĀÁȂ AAAAAAA!
:Message consists of all As, with different letters distinguished using diacritics.

{{comic discussion}}

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

Talk:3039: Human Altitude

2025-01-18T05:55:03Z

172.69.246.150:

I splurged a few paragraphs to try to deal with each detail (and a few things not ''directly'' obvious, but related). However, it's a mess and here (UK) it's basically past my bedtime and I have an early(ish) start tomorrow so... I know that if I had spent another half hour on it, it would have been tighter (less florid?), and would be linking to Yuri Gagarin, Montgolfier, Hubble, man-capable chinese kites, the likes of George Cayley, etc. And I never actually ''mentioned'' the Title Text, though the last paragraph I put is sort of relevent so might just need an "In the title text, it says ..., and, as it happens, ...". I shall leave it up to the editing-gods as to whether my sacrifice is acceptable or entirely in vain... Such is life! And so, goodnight. [[Special:Contributions/172.68.205.119|172.68.205.119]] 01:39, 18 January 2025 (UTC)
:I linked up a couple Wikipedia articles with [[Template:w]] and wish I could add all of those things, but alas: today’s the last day of the semester on a 3 day weekend here in the States and I’ve been sick all week. I’m going to be going now to work on my missing assignments and hopefully finish them, really wish that we can finish up the explanation as quick as we usually do! '''[[User:42.book.addict|42.book.addict]][[User talk:42.book.addict|Talk to me!]]''' 01:48, 18 January 2025 (UTC)
It seems strange how jagged this is and how low the lows are. Since roughly 1930 (certainly since 1940 at the very latest) someone, somewhere in the world has been flying in an airplane, at a minimum of probably 4.5km for the lowest person. And since like 1955 there's always at least someone over like 7km roughly, and since the jet age like 10km+. This isn't the kind of carelessness that xkcd is known for, unless I'm missing something.[[User:Kchinger|Kchinger]] ([[User talk:Kchinger|talk]]) 03:27, 18 January 2025 (UTC)kchinger

Some of the text (both in the explanation and the "into snow or water" in the title text) seems to suggest a "who wasn't shortly killed" that isn't stated in the chart. [[Special:Contributions/172.69.246.150|172.69.246.150]] 05:55, 18 January 2025 (UTC)

Talk:2943: Unsolved Chemistry Problems

2024-06-08T16:05:47Z

172.69.246.150:

P stands for poncentration, SMH my head 😒 --[[Special:Contributions/172.70.162.211|172.70.162.211]] 21:22, 7 June 2024 (UTC)

Is 'depolymerization' in this context referring to means of chemically recycling plastics? As I understand it, we basically just do recycling of thermoplastics at the moment by physically melting them, whereas being able to split a plastic apart into its component monomers would in principle enable a completely closed loop lifecycle for plastics, easing the strain on dwindling oil reserves and landfills and whatnot. Since these are supposed to be important unsolved problems, I feel like it probably is a reference to this, but I'm not a chemist and there may be something else which makes more sense. [[Special:Contributions/162.158.33.134|162.158.33.134]] 22:37, 7 June 2024 (UTC)
:In a chemistry context, depolymerization is simply the process of breaking down polymers into monomers. Plastic recycling is one potential application. Another is production of biofuels. It's a well understood process (usually just heat it up enough and/or apply the proper chemical treatment). Getting the desired outputs in an efficient manner is, in some cases, an unsolved problem. [[Special:Contributions/172.69.246.150|172.69.246.150]] 16:05, 8 June 2024 (UTC)

i've always been taught that the p stood for "parts". [[user talk:lettherebedarklight|youtu.be/miLcaqq2Zpk]] 04:01, 8 June 2024 (UTC)

:In chemistry, I was taught that it was "potential". I didn't even know this was in dispute. [[User:L-Space Traveler|L-Space Traveler]] ([[User talk:L-Space Traveler|talk]]) 04:54, 8 June 2024 (UTC)

P does not stand for anything. Originally, it was contrasted with q. Sørensen was performing electrochemical experiments and contrasted the reference electrode q with the hydrogen electrode p. Using p and q like this is common, like using x and y, u and v, or m and n. It's not an abbreviation, just a variable name. He recommended normalizing the concentration of hydrogen ions (i.e. dividing it by 1 mol/l) and calling the result Cₚ or C_q (depending on the electrode). Then each of these tends to be a small number, which we could write as 10^(-p) or 10^(-q). The number p⁺_H then represented the negative log of the normalized concentration of hydrogen cations at the hydrogen electrode. You can read about it in "The origin and the meaning of the little p in pH" by Jens G. Nørby, published in Cell. The associations with words like "power" and "potential" are now widely considered urban legends. [[Special:Contributions/172.70.134.39|172.70.134.39]] 04:55, 8 June 2024 (UTC)