explain xkcd - User contributions [en]

Talk:1237: QR Code

2026-05-05T06:26:28Z

2001:A62:5F7:FB01:BF80:8165:D7C9:B014: reference to 1988

It might be a pun on '''Quick Response''' Code --[[Special:Contributions/109.91.114.82|109.91.114.82]] 10:25, 12 July 2013 (UTC)
: It's not a pun, it's a widely used abbreviation [[User:Hippyjim|Hippyjim]] ([[User talk:Hippyjim|talk]]) 11:25, 12 July 2013 (UTC)
:: I meant that needing to scan it in 12 seconds might be a pun on "Quick Response". --[[Special:Contributions/93.232.203.46|93.232.203.46]] 14:11, 12 July 2013 (UTC)
The only real way would be to screenshot, print, and scan... possible in about 30 seconds. Anyone want to run a time trial?--[[Special:Contributions/69.140.11.243|69.140.11.243]] 11:05, 12 July 2013 (UTC)
: No it's possible. With the right Emacs command and a Delorean [[User:Hippyjim|Hippyjim]] ([[User talk:Hippyjim|talk]]) 11:25, 12 July 2013 (UTC)

:What about simply using other phone or camera to make a photo and display it on its display for the camera of this phone? BTW, why are the phones so stupid they can't display two applications at once? -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 11:30, 12 July 2013 (UTC)
:: [[1988]] is not an answer to your last question, but at least you are not alone with these worries. --[[Special:Contributions/2001:A62:5F7:FB01:BF80:8165:D7C9:B014|2001:A62:5F7:FB01:BF80:8165:D7C9:B014]] 06:26, 5 May 2026 (UTC)

You can take a screenshot of your screen (at least in Android) and then read the image with your qr-reading-program. Then it'll display the decoded QR-code, and you'll type it in the app. [[Special:Contributions/189.125.162.182|189.125.162.182]] 14:00, 12 July 2013 (UTC)
:The title text says that additionally the checksum of the camera is checked. So no trick with screenshots would be possible. However I don't see a problem with second camera which displays the photo (as suggested above). --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 14:05, 12 July 2013 (UTC)
::Can somebody explain how the checksum works, i.e. what the checksum against, why screenshot won't works? [[User:Arifsaha|Arifsaha]] ([[User talk:Arifsaha|talk]]) 16:08, 17 July 2013 (UTC)

I think that most phones and computers are kind of shoddily programmed, like the developers never take enough time to think of conveniences or solve problems. For example, I should be able to scan QRCs that are on my own screen. [[Special:Contributions/24.98.10.180|24.98.10.180]] 17:29, 12 July 2013 (UTC)
:That's a great idea! Shouldn't a browser be able to interpret them and just make it clickable, like a link? Seems straightforward. --[[User:DanB|DanB]] ([[User talk:DanB|talk]]) 12:32, 13 July 2013 (UTC)
::It's not that easy, an image is just an image. We would need a tag like <barcode-image>, maybe available at HTML 6.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:36, 13 July 2013 (UTC)
::Putting a QR Code on a webpage wouldn't make sense in the first place, unless it is intended to be read by smart phones. But I don't think it would be very hard to implement. Just pass every image on a webpage to a QR decoder (which of course also detects if something is a valid QR code). --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 14:16, 13 July 2013 (UTC)
:I see a potential security flaw if a program can arbitrarily screenshot the system it's running on (in this case to find the QR code, which would be indeed an initially bad design flaw in the installation process). Or course PC programs ''can'' screen-grab the screen that they're running on, I know because I've done this myself (for legitimate reasons) so maybe my objections on the grounds of security are moot. [[Special:Contributions/178.98.50.23|178.98.50.23]] 05:32, 16 July 2013 (UTC)
::I can't see a severe problem with that (nothing more dangerous than using arbitrary programs on a smart phone in the first place). Especially, I can't see any problem at all, with a browser scanning the content, which itself is rendering. --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 09:38, 16 July 2013 (UTC)

What about using mirrors? That'd be doable. [[Special:Contributions/88.200.105.99|88.200.105.99]] 12:53, 13 July 2013 (UTC)

I've actually needed to do this once. I was browsing the web on my phone and it only displayed a QR code to download an app I needed. I wondered what the least number of mirrors required would be to achieve this. Assuming it doesn't read inverse images, it would be necessary to flip it on both axes. [[User:Keavon|Keavon]] ([[User talk:Keavon|talk]]) 05:36, 14 July 2013 (UTC)
: QR codes are invariant upon rotation, but not upon reflection. So yes, you'd need at least two mirrors (or any even number of them). [[Special:Contributions/88.24.184.87|88.24.184.87]] 17:09, 15 July 2013 (UTC)
:Same idea! And here I was thinking that I was immune to nerd sniping. ProTip: nobody who would ever want to look at this website is immune to nerd sniping. I think that four would be the minimum- one for the camera, one to redirect, then two more. [[User:RedHatGuy68|RedHatGuy68]] ([[User talk:RedHatGuy68|talk]]) 06:27, 10 February 2016 (UTC)
::And you'd need to make a photo without changing the content of your screen. I think the solution with making a photo with a second device is still the easiest (assuming, you have one at hand) --[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 09:38, 16 July 2013 (UTC)

It's not hard. All you need is to move your phone faster than light for a short distance, and tadaa, you have scanned it. [[Special:Contributions/84.197.94.196|84.197.94.196]] 19:06, 15 July 2013 (UTC)

;Link at Transcript

I think the link should be shown at "Explanation". I can't see it at the original comic, so "Transcript" is the wrong section.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 17:11, 12 July 2013 (UTC)
:OK, understood. I just did not try to read that QR code. But the link is still not correct at "Transcript", you have to do some actions to figure out and so it still belongs to "Explanation".--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:13, 12 July 2013 (UTC)

;Real-life use for something like this

Before I saw the title text, I thought the scenario involved scanning one device's display on another device to set up a key exchange between applications on the two devices, sort of like a [http://bu.mp/ Bump]. --[[User:Tepples|Tepples]] ([[User talk:Tepples|talk]]) 00:35, 13 July 2013 (UTC)

Isn't there this software on the computer for seeing an iPhone's display on the computer? If you have it, just scan it. If its an android it won't work. [[Special:Contributions/188.29.164.92|188.29.164.92]] 13:03, 25 October 2013 (UTC)

; SOLUTION!!!

Mirrors in a certain formation! {{unsigned ip|108.162.218.148}}

Quick Google-Lens access on the screen kinda ruined the joke. But it was funny for about 8 years, that's not bad for a technology joke, and now it's also wierdly nostalgic.

Talk:2358: Gravitational Wave Pulsars

2026-04-17T18:20:31Z

2001:A62:5F7:FB01:BF80:8165:D7C9:B014: Previous commenter had forgotten to close the parenthesis

This actually an old joke "what is the secret of comedy"
[[User:Steve|Steve]] ([[User talk:Steve|talk]]) 07:58, 13 September 2020 (UTC)

This one isn't very funny..
[[Special:Contributions/162.158.75.190|162.158.75.190]] 19:37, 11 September 2020 (UTC)
::It's not topical either. I sense filler. [[Special:Contributions/162.158.186.100|162.158.186.100]] 19:49, 11 September 2020 (UTC)
::::Perhaps not as topical as US Presidential Elections or COVID-19, but there have been at least two research papers on gravity wave phenomena in the past two weeks, I’ve been seeing YouTube vids about it pop up in my feed and various people tweeting about it. See the research paper, "GW190521: A Binary Black Hole Coalescence with a Total Mass of 150 Solar Masses," which was published in Physical Review Letters on September 2, 2020 and The research paper, "Properties and Astrophysical Implications of the 150 Solar Mass Binary Black Hole Merger GW190521," published in Astrophysical Journal Letters on September 2, 2020. [[Special:Contributions/108.162.219.58|108.162.219.58]] 05:13, 12 September 2020 (UTC)
::Unless there's a hidden joke that I don't get [[Special:Contributions/172.68.141.176|172.68.141.176]] 20:05, 11 September 2020 (UTC)
::There's a common joke that roughly goes "What is the secret to a good joke timing?" (said all at once) [[Special:Contributions/162.158.106.244|162.158.106.244]] 21:18, 11 September 2020 (UTC)

Context is here: https://arxiv.org/abs/2009.04496
::Related to this? [[https://en.wikipedia.org/wiki/GW190521 GW190521 Wiki]] [[User:OhFFS|OhFFS]] ([[User talk:OhFFS|talk]]) 21:13, 11 September 2020 (UTC)
::No, the gravitational waves have different periods than what LIGO/Virgo detects, and therefore the astrophysical sources are different. [[Special:Contributions/162.158.75.200|162.158.75.200]] 21:22, 11 September 2020 (UTC)

This is a reference to the (possibly apocryphal) Johnny Carson interview of a comedian (possibly Jerry Lewis, possibly Buddy Hackett):
* Comedian: Go ahead: ask me what is the secret of comedy.
* Carson: OK, what is the...
* Comedian: TIMING!
I've looked for the source, and all I can find are retellings of retellings (e.g. https://www.sleuthsayers.org/2013/08/the-immortal-timing-of-elmore-leonard.html ). -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 02:35, 12 September 2020 (UTC)

I think the title text is referring to the saying I’m realty that the most important things to consider when buying a house are “location, location, location.” (https://www.realestateabc.com/insights/location.html)
[[Special:Contributions/108.162.238.5|108.162.238.5]] 03:34, 12 September 2020 (UTC)
:Which is good to know, but leaves some doubt over momentum, momentum and momentum. [[Special:Contributions/162.158.158.197|162.158.158.197]] 08:24, 12 September 2020 (UTC)

The use of curly braces around {location, location, location} might also be a joke.
"...using curly braces refers to the character vector that is stored within the string."
https://www.sciencedirect.com/topics/engineering/curly-brace
I don't understand enough about the topic to be sure. ---- JM
::The link points to a specific syntax for one programming language, namely MATLAB. Other languages use {...}, of course, but equally common is (...) or [...]. But importantly it is not a standard math/physics/astronomy notation. In a paper, unless otherwise specified, (x, y, z) is a triple of numbers making a vector whereas {x, y, z} is the set containing x, y, z and nothing else, which might therefore have 1, 2 or 3 elements. If there’s any joke here, it’s that {location, location, location} = {location}.

I've forgotten 110% of what I learned about math, but I thought {length, length, length} (or, equivalently, angle and magnitude) were equally important to a vector in 3-space. [[Special:Contributions/172.69.62.160|172.69.62.160]] 18:22, 12 September 2020 (UTC)
:([Coming in three+ years later] A triplet like (1,2,3) can be treated as a vector in 3-space. Consider it the termination of a line segment extending out from the origin (0,0,0). You now have a direction (the way the segment points) and a magnitude (its length)--that is, a vector. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 03:41, 18 November 2023 (UTC)
:: [[859]] --[[Special:Contributions/2001:A62:5F7:FB01:BF80:8165:D7C9:B014|2001:A62:5F7:FB01:BF80:8165:D7C9:B014]] 18:20, 17 April 2026 (UTC)

I don't understand enough about the topic to be sure. ---- breadontoast
she also delivers a demonstration on the detection method as a passing gravitational wave will lead to the Radiobursts being slightly out of sync to their expected timing

There is also another joke that vectors only encode direction not location. To get a location a vector must be applied to another location e.g. a vector relative to the origin.

This comic is also reminiscent of this knock-knock joke: "Knock, knock." "Who's there?" "Interrupting cow." "Interrupting co--" "MOO!" [[Special:Contributions/108.162.219.92|108.162.219.92]] 13:11, 18 September 2020 (UTC) delete-if-unhelpful

Talk:3203: Binary Star

2026-02-05T08:24:29Z

2001:A62:5F7:FB01:BF80:8165:D7C9:B014: reference to 1029

here before the explanation [[User:Qwertyuiopfromdefly|Qwertyuiopfromdefly]] ([[User talk:Qwertyuiopfromdefly|talk]]) 04:47, 5 February 2026 (UTC)

Me too [[Special:Contributions/115.70.50.73|115.70.50.73]]

It was me as well :::;) [[Special:Contributions/216.25.182.141|216.25.182.141]] 05:34, 5 February 2026 (UTC)

Randall has been, uh, funnier… I thought I must be missing something, a clever joke or some astronomers insider, but no—that's really all there was to it. Well.

Nice to see that Randall has graduated from the woes of [[1029]], and now can draw Morocco-style stars :-) --[[Special:Contributions/2001:A62:5F7:FB01:BF80:8165:D7C9:B014|2001:A62:5F7:FB01:BF80:8165:D7C9:B014]] 08:24, 5 February 2026 (UTC)