explain xkcd - User contributions [en]

1806: Borrow Your Laptop

2023-06-23T20:15:07Z

108.162.245.245: 1787 is 5 years old now, so I don't think it counts as recent.

{{comic
| number = 1806
| date = March 3, 2017
| title = Borrow Your Laptop
| image = borrow_your_laptop.png
| titletext = If used with software that could keep up, a scroll wheel mapped to send a stream of 'undo' and 'redo' events could be kind of cool.
}}

==Explanation==
[[White Hat]] asks to borrow [[Cueball|Cueball's]] laptop to view something (possibly a website). Cueball permits this, but immediately begins rattling off a list of very unusual key- and mouse-bindings that he has applied to the device. In the caption, [[Randall]] states that he himself tends to continually re-configure computers that he owns in weird ways, eventually rendering it unusable or at least unpleasant to use for others.

Of the three items in Cueball's list of customizations only the first and half of the second seems like a real and relevant changes.

At first he has programmed the computer so that hitting both shift keys simultaneously will change the keyboard back to QWERTY. The {{w|QWERTY}} keyboard is the standard in the US (as well as some other places using the roman alphabet). This implies that Cueball prefers a different keyboard layout, (most likely the {{w|Dvorak Simplified Keyboard|Dvorak}} keyboard layout, see [[#Trivia|trivia]]), but doesn't need the printed letters to match up with those of the laptop. Cueball would have to make a special customization to make pressing the two shift key trigger this shift (see [[#Trivia|trivia]]). Presumably Cueball can later return to this favorite layout by pressing the shift keys again.

Cueball tells, in the first part of the second point on the list, that he has changed his keyboard layout so that {{w|capslock}} acts as the {{w|control key}} (Ctrl). Swapping capslock and control is a common thing to do in the world of enlightened users on {{w|Unix}} or for users of the {{w|Emacs}} [https://www.emacswiki.org/emacs/MovingTheCtrlKey editor]. The "Caps Lock" key (immediately to the left of the "A" in a traditional layout) is much easier to reach for a touch typist than the more out-of-the-way "Ctrl", and the latter is often used more frequently, especially by programmers.

However, the second part where Cueball says he has then moved capslock so that it is activated when hitting the {{w|spacebar}} makes no sense. It is quite impractical, as the spacebar is the largest key and it will not gain anything from being used for anything other than spaces, especially not a rarely used key that locks into capital letter mode move when activated. It would make the common accidental application of capslock more likely. And what is worse he doesn't tell White Hat where he has put the space bar function, making it impossible to write a simple text, although he could try to see what the Ctrl keys does now...

Finally Cueball goes out on a limb with an impossible setting, which is that his laptop is setup so that scrolling [[:Category:Time travel|moves through time]] instead of through "space" (as in up and down on the screen). This refers to {{w|spacetime}}, a common model in relativistic physics. The feature in only activated when using {{w|Touchpad#Operation_and_function|two-finger scroll}}, which is often used on {{w|Touchpad|touchpads}}/track pads for laptops as a gesture for scrolling. The title text may suggest that "moving through time" may pertain to undo/redo, or perhaps browser history.

Finally it becomes clear these three settings are not the only important changes, as Cueball's list continues with at least one other point which he doesn't get to finish in the comic. Thus the list may be much longer than four points.

In the title text Randall says that he would actually find a feature where the {{w|scroll wheel}} was mapped to send a stream of {{w|Undo|undo/redo}} commands would be kind of cool. (Notice he is no longer talking about the two-finger scroll from the comic). But only if used with software that could keep up with such a feature. He thus indirectly states that many programs would not be able to keep up. For an example of what this might look like, many digital artists record timelapse footage of their art, which could be thought of as a continuous string of redo commands (occasionally broken up by undo commands whenever the artist needs to correct a mistake).

Outside of art programs, such continuous undo/redo action would produce unexpected and chaotic results. This could also indicate that this was a similar feature that Cueball was referring to when talking about moving through time with the two finger scroll in the main comic. So not as in the computer traveling through time, but rather scrolling through the previous actions performed on the computer, as in moving through the computers past.

People often have reasons to change their keyboard layouts on laptops, due to the reduced keyboard, which can leave vital keys out. Rather than change the keyboard layout all the time in order to access keys which are not accessible in one of the layouts, one can take advantage of text substitution and keyboard remapping programs to set shortcuts for keys they use often.

==Transcript==
:[White Hat walks toward Cueball's desk pointing at his laptop while looking back at Cueball standing behind him.]
:White Hat: Can I load it up on your laptop?
:Cueball: Sure!
:Cueball: Oh, just hit both shift keys to change over to QWERTY.
:Cueball: Caps lock is control. And spacebar is capslock.
:Cueball: And two-finger scroll moves through time instead of space.
:Cueball: And–

:[Caption below the panel:]
:Once I've used a computer for a while, no one else will ever use it again.

==Trivia==
*It has been a recurrent theme for Randall to refer to the {{w|Dvorak Simplified Keyboard|Dvorak}} keyboard layout, and, although he doesn't say so, it seems safe to assume that this is the current setting, as it is one of the most common QWERTY competitors, and has been [[:Category:Dvorak|repeatedly referenced]] in xkcd.
:Supporters claim that typing speed is faster on a Dvorak keyboard, although this is still contentious, and this is a reason Randall often makes jokes about it as can be seen in the category referenced above.
*The laptop most likely has a standard QWERTY keyboard, but if Cueball can type blindly in Dvorak he would not be troubled by the fact that the keys typed a different letter than what is on the keyboard's key.
*In the comic [[1787: Voice Commands]], which directly references Dvorak, Cueball is shown to be able to speak the QWERTY version of a Dvorak keyboard layout, proving that he really knows by heart the relation between these two settings used on a QWERTY keyboard layout.
:The same problem would arise if the computer is set to another language than the keyboard layout, which often happens in countries where more than one language is common.
*The shift key is a modifier key and in general it requires a second non modifier key to trigger an action. Furthermore the user interfaces in most operation systems don't distinguish between the left and right shift key.
:Nevertheless by doing some registry hacking (Windows) or editing configuration text files (UNIX/Linux) it is possible to reach Cueball's approach. The simpler and operating system independent approach would be to use a programmable keyboard, such as a keyboard using QMK firmware [https://qmk.fm/]
:A typical classic configuration for the shift key in Windows is by pressing one of the shift keys five times in a row it turns on a ''Sticky Key'' notice, where the ''Ease of access center'' enables people with for instance only one hand to be able to reach Ctrl+Alt+Delete or other combinations on which two hands are needed.
*A day after the release of this comic, a user on reddit [http://www.reddit.com/r/emacs/comments/5xi92h/a_scroll_wheel_mapped_to_send_a_stream_undo_and/ suggested] a way to make the undo-redo-scrolling work in emacs using undo-tree. It uses shift-scrolling to avoid conflicts with normal scrolling.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Computers]]
[[Category:Time travel]]
[[Category:Time]]

Talk:2529: Unsolved Math Problems

2021-10-17T07:36:11Z

108.162.245.245:

Center panel possibly related to "The drunkards walk" and theories on randomised motion.
https://www.quantamagazine.org/random-walk-puzzle-solution-20160907/
More references https://mathworld.wolfram.com/RandomWalk.html

Someone's gotta point out that "walking randomly on a grid, never visiting the same square twice" would rapidly trap you in a corner (even the example has a 50/50 chance of that happening on the next move) [[Special:Contributions/172.70.130.125|172.70.130.125]] 04:29, 16 October 2021 (UTC)

Not if it's an infinite grid.

I think there's two different ways to interpret the question - as a uniform random element of the set of all non-self-intersection NxK length paths, in which case it's fine, or as a path defined by a random walk in which moves onto your own path are not allowed, which doesn't seem well defined, since you might end up in a situation where you are surrounded by your own path and cannot continue for all NxK steps.

An early example of a cursed problem is the Cantor Function. https://en.wikipedia.org/wiki/Cantor_function

I admire whoever wrote the description of the curve in the "cursed" panel. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 05:36, 16 October 2021 (UTC)

"Algebreic" is a misspelling of "algebraic". Could Randall really have made this mistake, or is it another malamanteu? What does "breic" come from? [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 06:10, 16 October 2021 (UTC)

I wonder if Randall was actually referring to that quote about "Into the Woods", or he just thought "Sondheim calculus" sounded cool and it was a total coincidence. I found it when I googled "sondheim calculus" to make sure it wasn't a real thing. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 06:29, 16 October 2021 (UTC)

In panel 2, what would 'k' be? [[Special:Contributions/172.69.35.108|172.69.35.108]] 08:00, 16 October 2021 (UTC)

'k' would represent the number of marbles placed on the ground. [[Special:Contributions/162.158.88.127|162.158.88.127]] 08:09, 16 October 2021 (UTC)
:Though probably correct, I think the implied state is that an integer multiple (k) of N steps is made (s=N*k), with that number of marbles dropped, not s=(N*k)+c steps (for N>c) which would have the same result (uselessly) for all values of s where c ranges 0..N-1. It just introduces inflections into the graph (with s as an axis) that needn't be there (with just a k-based one). Or, in other words, selectively poll all s-values that are exactly divisible by N, and forget all the rest. (That divisor is k, and hence k is the number of marbles. Or perhaps k+1 if you leave one on the starting spot too.) [[Special:Contributions/162.158.159.25|162.158.159.25]] 21:59, 16 October 2021 (UTC)

To me, the cursed curve looks a bit like a crosier https://commons.m.wikimedia.org/wiki/File:Crosiere_of_arcbishop_Heinrich_of_Finstingen.jpg

--> I had the same impression and added it. --[[Special:Contributions/162.158.94.219|162.158.94.219]] 11:40, 16 October 2021 (UTC)

No explanation of the "Euler Field Manifold Hypergroup (Isomorphic to a)..." part?

The cursed curve looks almost like someone took a graph of the Binet formula in the complex plane, stretched it out a bit, and rotated it onto the i axis.
: This was my first thought too when I saw it. [[Special:Contributions/172.69.34.87|172.69.34.87]] 17:16, 16 October 2021 (UTC)
: It looks like Vulcan script to me. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 13:51, 16 October 2021 (UTC)
: That's what it looks like to me too; recognized it from that Numberphile video on Fibonacci numbers in the complex plane [[Special:Contributions/108.162.245.245|108.162.245.245]] 07:36, 17 October 2021 (UTC)

Could the cursed curve be a reference to the logistic map?

Can someone produce a high resolution image of the Cursed Curve? It needs to be on a T-shirt [[User:Avimimus|Avimimus]] ([[User talk:Avimimus|talk]]) 21:39, 16 October 2021 (UTC)

Is someone going to mention the title text?

I swear I've seen that third plot, I thought it was in XKCD, but a quick run through tagged entries didn't find anything... unfortunately I consume a lot of math media so I can't place it. It's bugging me so I hope this note will serve as encourgement to someone that DOES remember [[Special:Contributions/162.158.106.221|162.158.106.221]] 21:29, 16 October 2021 (UTC)

Are there any examples of "cursed" math problems? I've seen "weirdly abstract" and "weirdly concrete" ones, but not "cursed" ones. [[Special:Contributions/162.158.63.117|162.158.63.117]] 01:03, 17 October 2021 (UTC)

Talk:1052: Every Major's Terrible

2021-10-11T16:36:12Z

108.162.245.245: added a comment

I think Iambic Octameter has a ''stressed-unstressed'' pattern, not the other way around as this explanation says. [[Special:Contributions/172.68.34.4|172.68.34.4]] 02:56, 10 April 2017 (UTC)
:No, the explanation is correct, I misread the Wikipedia article. [[Special:Contributions/172.68.34.4|172.68.34.4]] 13:41, 16 April 2017 (UTC)

Panel 1's cueball is in the same pose as Rodin's "The Thinker"

Panel 4 background is the periodic table of elements.

Panel 5, Fowler's Toad emits a noxious secretion that irritates skin and mucous membranes (it was previously thought to cause warts)

Panel 6, Psychology = a serial killer with a chainsaw, Sociology = hobo; Social Psych = hobo serial killer with chainsaw.

Panel 15, LISP, Scheme, and other computer languages with an excess of parentheses.

Panel 16, biohazard symbol

Panel 19, bongos were played by Richard Feynman

Panel 27, fear of snakes, study of reptiles

Panel 28, a picture of a stomach, pun on "stomach" being slang for "tolerate"

Panel 30, words in all lowercase like e.e.cummings

-- [[Special:Contributions/75.103.23.206| 75.103.23.206 ]] 22:04, 7 December 2012‎
:Hobo serial killer with chainsaw? Social psych sounds awesome!
:[[Special:Contributions/24.2.217.188|24.2.217.188]] 22:42, 22 October 2013 (UTC)
----
In panel 22 (History), what's the theme connecting the years 1935, 1969, and 1991?
[[User:Wwoods|Wwoods]] ([[User talk:Wwoods|talk]]) 15:40, 21 May 2013 (UTC)
:1935 is certainly related to some event that lead to the WWII (a quick look at the Wikipedia page for 1935 show that was the year Hitler rearmed Germany), which paved the way to the Cold War. 1969 was Apollo 11, a high moment of the Cold War, as the USA essentially won the race to the Moon. And 1991 was the year that the USSR dissolved, officially ending the Cold War. [[User:Sir labreck|Sir labreck]] ([[User talk:Sir labreck|talk]]) 18:37, 11 August 2015 (UTC)
:1935, Harlem race riot; 1969, race riot in Kuala Lumpur, Malaysia; 1991, Rodney King race riots... 2014-2016??? [[Special:Contributions/173.245.54.62|173.245.54.62]] 03:33, 13 December 2015 (UTC)
:Although the race riot dates match, I think war related is more likely. 1935 (WWII), 1969 (Vietnam), 1991 (Gulf War) I'm not sure what the common thread is, though, and 'war' is too broad [[Special:Contributions/172.69.250.4|172.69.250.4]] 20:37, 30 September 2018 (UTC)
::{{w|WWII}} began in '''1939'''. The {{w|Vietnam War}} was 1955-1975 and {{w|Gulf_War_(disambiguation)|Gulf War}} is ambiguous. Just sayin... --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 20:34, 1 October 2018 (UTC)
----
This explanation is very small for that big comic. I am starting to add the transcript and after that I will do more investigations to that opera. This should be the key to explain all the panels.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 19:13, 21 May 2013 (UTC)

:The answer won't lie in the song, trust me. Pirates of Penzance is probably my favorite comic opera out there. Plus Randall gives that the lie in saying you can use the tune from the elements song (a well-known parody) or even Marry Poppins (similar tune, but not exactly the same). I think each panel is just a reference to the words, I don't think that Randall is actually involving The Pirates of Penzance in any way other than the tune. [[Special:Contributions/173.245.52.211|173.245.52.211]] 20:53, 9 December 2013 (UTC)
----
Feynman was also known for being a ladies' man, so the two girls in panel 19 are significant IMHO.
--[[Special:Contributions/141.101.80.117|141.101.80.117]] 13:51, 25 December 2013 (UTC)
----
Needs explanation what does it mean to '''choose a major''', and what '''major''' is in this context. Note every reader is from U.S.A.; different countries have different higher education systems. --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 10:56, 9 January 2014 (UTC)
:True that. 'Graduation' in Brazil means 'Undergraduation' in the US. [[Special:Contributions/108.162.254.105|108.162.254.105]] 03:51, 1 February 2014 (UTC)
----
"Math's just physics unconstrained by precepts of reality" - that isn't a binary tree, its a [http://en.wikipedia.org/wiki/Bifurcation_diagram bifurcation diagram] from chaos theory. And, sorry, it has nothing to do with the Banach–Tarski paradox - that's just mindless name-dropping.
[[User:Davidbak|Davidbak]] ([[User talk:Davidbak|talk]]) 20:54, 10 February 2014 (UTC)
:Are you sure it is not just an illustration of Banach-Tarski, arguably the most famous example where mathematical reality and (physical) intuition diverge? Why would the verse be illustrated by a bifurcation diagram (which I think, and I might be a bit ignorant here, is a concept pretty much only found in the "applied side" of mathematics, which ''is'' constrained by precepts of reality)? And even if it were a bifurcation diagram, why would the mass of the balls change? (again, I am perhaps showcasing my ignorance; if so, please be gentle) Finally, i would deem the bifurcation explanation a bit too obscure to be the real deal - a panel which is only understood by somewhat specialized mathematicians seems strange to me, especially given that all other frames contain understandable references. [[Special:Contributions/108.162.229.183|108.162.229.183]] 13:38, 9 October 2015 (UTC)
https://www.youtube.com/watch?v=pRexBMPeRTo[[User:Halfhat|Halfhat]] ([[User talk:Halfhat|talk]]) 18:59, 3 April 2014 (UTC)
:That is distinctly a bifurcation diagram. Banach Tarski doesn't factor into this at all. Disagree-P 15:39, 20 Nov, 2020

Panel 30: possibly iambic septameter[[Special:Contributions/141.101.104.154|141.101.104.154]]

---
I think that the reason for not getting hugs in panel 16 is more to do with the fact that as a virus researcher you would be aware of how easy it is to get a virus/disease and so you would keep away from people and be worried about hugs because of that. (Sorry if I've done something wrong this is my first comment!) [[User:Yxquillio|Yxquillio]] ([[User talk:Yxquillio|talk]]) 08:24, 3 January 2016 (UTC)

Another song I guess could provide a good match is "Can You Stop the Calvary?" by Jona Lewie (or "Where's the Modding API" if you're a YOGSCAST fan like me. :)) --[[User:JayRulesXKCD|JayRulesXKCD]] ([[User talk:JayRulesXKCD|talk]]) 11:50, 20 September 2016 (UTC)

"End of the first verse where Cueball tells his academic advisor that he is undecided as every major's terrible. He even throws away his study guide." Are you sure it's not a course catalog? [[Special:Contributions/108.162.212.59|108.162.212.59]] 10:33, 19 June 2017 (UTC)

I think I should add that Pratchett used that quote to prove that geography was not a boring science, as it is physics, which is exciting, with some trees on it. Just a thought.[[User:MrBookBoy|MrBookBoy]] ([[User talk:MrBookBoy|talk]]) 01:30, 22 May 2018 (UTC)

Hey, the cs parens are missing a close paren. Like literally. Lol. [[User:Sarah the Pie(yes, the food)|Sarah the Pie(yes, the food)]] ([[User talk:Sarah the Pie(yes, the food)|talk]]) 15:00, 22 May 2021 (UTC)
----
It should be noted that in panel 35, they're referring to "Sophie's Choice." A movie in which the protagonist has to decide which of her two children to save, and which one to kill.
--[[Special:Contributions/108.162.245.245|108.162.245.245]] 16:36, 11 October 2021 (UTC)

2525: Air Travel Packing List

2021-10-07T21:27:54Z

108.162.245.245: Changed some absolute speech to show there were some common exceptions, removed some redundant phrasing, corrected some minor grammatical errors.

{{comic
| number = 2525
| date = October 6, 2021
| title = Air Travel Packing List
| image = air_travel_packing_list.png
| titletext = I know the etiquette is controversial, but I think it's rude when the person in front of me reclines their seat into the bell of my trumpet.
}}

==Explanation==
{{incomplete|Created by an TRUMPETBORNE PARACHUTER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic is about a proposed air-travel packing list, and the humor is that many people who have not been flying during Covid might have forgotten what to pack. Most of the items are already found on the plane, SOUND like they would be useful on a plane, or could be useful in (the unlikely event of) a plane crash. Here is a quick summary of each:

{| class="wikitable"
! Item
! Explanation
|-
|Seat cushion
|This can be used as a flotation device in a crash and is provided by the airline. Some people may also bring their own cushions for comfort.
|-
|{{w|Parachute}}
|Parachutes are normally used to slow down your falling out of the sky to a relatively safe speed in case of a severe problem with your aircraft, and are routinely used as a safety device by (para)glider pilots, test pilots, military aircraft crew and in similar situations when being unable to land safely is a significant concern. A parachute won't be very useful in a typical passenger airplane (even a small one) as there is no way to safely exit such a plane in-flight. Even the airplanes used to voluntarily exit from while they're perfectly good (as some crazy people do) need to be specifically designed or modified for the purpose such as having wide sliding doors that are unaffected by airflow. However, there were single cases of people being ejected or sucked out of a passenger airplane; in such case a parachute could by arguably useful. Famously, [[:Category:Comics featuring D. B. Cooper|D.B. Cooper]] jumped from an airplane in-flight with a parachute.
|-
|Wing glue
|Probably to repair wings in the event of damage, potentially in a crash. Would be tricky (but not necessarily impossible) to apply mid-flight. This the first of several items that are potentially useful to the flight crew or maintenance teams, but would not be useful or appropriate for passengers to bring aboard.
|-
|{{w|Air horn}}
|An air horn uses compressed air to make a very loud noise very easily. This may be important for drawing attention to yourself in the event of a crash. Typically, emergency lifejackets on a plane are provided with a light and whistle for this purpose. The noise of an air horn might prove more effective for this purpose than a whistle, but it would become useless as soon as the compressed air ran out. Its inclusion is probably meant to suggest that the word 'air' in its name indicates that it's designed for use in an aircraft. Using one in a non-emergency situation would infuriate everyone else on the plane.
|-
|{{w|Sextant}}
|In combination with star charts, a sextant can be used to determine your position based on the location of stars in the night sky. Alternately, in combination with an accurate clock, a sextant can be used to determine the position of the sun relative to the aircraft to determine the vehicle's position. In a crash, you could use this to find your way to a safe place, but sextants are rarely used, and most people not trained on how to operate one. GPS will also allow you to find your position, is built into many phones, and is faster and easier to use than a sextant. If you've got a homing beacon, it probably makes more sense to just activate that and wait for help to arrive.

Until the early 1980s, long-range airplanes had a {{w|Air_navigation#Flight_navigator|flight navigator}} who used sextants and {{w|celestial navigation}} to determine the position of the airplane. Interestingly, it was much more accurate than early {{w|inertial navigation systems}}, and the accuracy of celestial navigation is still useful today. What made the sextant redundant was the INS' lower workload - the error accumulated by the INS during a long oceanic flight could always and easily be mitigated by other means, for example with {{w|VHF omnidirectional range|VOR}}/{{w|Non-directional beacon|NDB}} radio beacons.
|-
|Nose plugs and goggles for pressure
|Nose plugs and goggles are commonly used in swimming but would be useless for dealing with cabin pressurization or depressurization. Since your mouth and nose are interconnected, nose plugs would be useless on their own. Trying to hold your breath in a sudden depressurization event will cause lung damage, so nose plugs wouldn't be a good thing, even if you could also seal off your mouth. Goggles would also not be useful. During depressurization, the air would just seep out. During pressurization, they would just become uncomfortable and difficult to remove.
|-
|Airplane shoes
|Airlines typically don't require the use of special footwear for passengers, nor do they provide special shoes. Before emergency egress, certain shoes (like high heels) must be discarded, though. Aircrew are also prohibited from wearing such shoes.
|-
|Navigation crystal
|Mystical form of navigation, presumably either for navigation during flight or to help you get home after a crash.
Crystals that polarize light can be used as a compass [http://www.polarization.com/viking/viking.html].
|-
|Spare batteries in case the plane runs out
|Airplanes will generally use more power than any battery small enough to be easily packed in a bag can provide. They will generally use either 115V AC at 400Hz or 28V DC, both of which are very uncommon outside of aviation. The plane will almost never use its own batteries in-flight anyway, getting its electric power from the main engines, the APU, or, in emergencies, the ram air turbine or similar generating device. The batteries are generally only used on the ground when the engines are not running.
|-
|{{w|Birdseed}}
|So one can attract birds. In practice, this wouldn't work for multiple reasons (high speed, altitude, and sealed windows being some of most obvious ones) and would pose a significant hazard of birds getting stuck in an engine if it did. On the other hand, spreading birdseed before boarding would be seen as misconduct by airport authorities, as it may pose a danger to aircraft by attracting birds. Alternatively, birdseed can be used to attract birds after surviving a crash, e.g. to catch them for food.
|-
|{{w|Homing beacon}}
|Once activated, a homing beacon will send out a continuous radio signal so that rescuers can find your location. These can be very useful in a plane crash, but airplanes already carry them ({{w|Emergency position-indicating radiobeacon}}s), so you don't need to pack one yourself. Incidentally, the {{w|COSPAS-SARSAT}} system for locating distressed airplanes and ships was a cooperation started by the United States and the Soviet Union, and it was an elegant and simple solution that uses the {{w|Doppler effect}} of radio signals for accurate location - long before the {{w|Global Positioning System}}.
|-
|Meteorite antidote
|Meteorites are pieces of space rocks that make it all the way to the ground. They can cause injury but they aren't poisonous{{Citation needed}}, so an antidote would not help.
|-
|USB wing connector
|This is a just a wire connector, but because it has wing in the name is on the list. Alternatively, the plane wings connect by USB, and this can be used to reattach wings. Airplanes usually use the {{W|ARINC 429}} protocol (or, increasingly, TCP/IP, RS427, RS232, or even CANBUS) instead of USB protocols to facilitate electronic communication between flight computers and the engines, for example.
|-
|Emergency siren
|USE IN CASE OF EMERGENCY
|-
|Spare flaps
|Flaps can be moved to adjust the lift/drag ratio of a wing, generally during takeoff and landing. Flaps are very large and mounted on the wing, outside the passenger compartment, so bringing spares would be very difficult and completely useless. Flaps failing to come down can also usually be remedied by just landing at a longer runway.
|-
|{{w|Mouthpiece (brass)|Mouthpiece}} (pandemic restriction; airlines still provide the trumpet)
|A part of a brass instrument like a trumpet. Randall jokes that trumpets are provided on airplanes (which would be very obnoxious to other passengers), but due to the pandemic you cannot use a shared mouthpiece.
|-
|Luggage ballast
|Likely to make plane more balanced. While balancing weight in a plane is indeed a real problem, it's solved by rearranging luggage and adjusting engine power slightly. Introducing ballast would mean additional weight for no real reason.
Alternatively, while a common passenger issue is to have hand- and/or hold-luggage that exceeds the airline's personal allowance, this person has ''under''weight baggage and does not wish to 'waste' the difference, so bulks it up. (Noting that someone already with the rest of the items on this list is unlikely to suffer this 'problem'.)
|-
|Flag (international flights)
|To identify your country of origin. Other flags are also used to communicate between boats without electricity, in the event the boats are in distress, so they could be used in the event of a crash.
|-
|Decoy tickets
|Maybe these would used as a distraction so you can sneak onto the plane without paying?
But also a typical trope for fictional (and real life?) attempts to evade being tracked or followed. Buy tickets for one destination, that one assumes the opposition will be fully aware of, but also arrange for another set (probably with a 'clean' identity) for your intended destination and switch to using those once in the chaos of the departure-lounge.
|-
|Keys to the plane
|Though some pushed for it after a plane was stolen in the {{w|2018 Horizon Air Q400 incident}}, most commercial planes do not require keys to start the engine(s) like a car does. Likewise, plane doors are not locked with a key. Instead, they are secured with a tamper seal. If a seal is found broken, the plane is thoroughly checked for any wrongdoing.
|}

The title text reference a common debate regarding reclining in airplanes. About half of the people think that reclining is rude as it takes up the space of the person behind. The other half think that seats recline for a reason and the person in a seat has the rights to the space behind them. That has resulted in actual physical fights. Here Randall sides with the anti-recliners, presumably because it would prevent him from playing the trumpet, the person in front will certainly argue that playing the trumpet is annoying, to which Randall could reply that because the trumpet is provided by the airline, he has the right to play it, adding a new layer to the debate.

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

<big>Air Travel Packing List</big>

If you haven't flown in a while, you might not remember what you need to bring. Use this handy checklist to pack!

[Two columns of lists of items. Each item is preceded by a checkbox.]
*Seat cushion
*Parachute
*Wing glue
*Air horn
*Sextant
*Nose plugs and goggles for pressure
*Airplane shoes
*Navigation crystal
*Spare batteries in case the plane runs out
*Birdseed
*Homing beacon
*Meteorite antidote
*USB wing connector
*Emergency siren
*Spare flaps
*Mouthpiece (pandemic restriction; airlines still provide the trumpet)
*Luggage ballast
*Flag (international flights)
*Decoy tickets
*Keys to the plane

{{comic discussion}}

2525: Air Travel Packing List

2021-10-07T04:08:57Z

108.162.245.245: /* Explanation */ Explained sextant

2521: Toothpaste

2021-09-28T13:58:51Z

108.162.245.245: /* Explanation */ Fixed grammar and sentence flow

{{comic
| number = 2521
| date = September 27, 2021
| title = Toothpaste
| image = toothpaste.png
| titletext = "9 out of 10 dentists have banned me from their offices."
}}

==Explanation==
{{incomplete|Created by JUST THE DENTIST (11th REGENERATION) - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
[[Cueball]] is telling [[Megan]] about his friend. He indicates that she said something shocking and probably hurtful. He then states that even though she tried to apologize it was too late, the words had been said and it cannot be taken back.

He uses a phrase to underline this: You can't put the toothpaste back in the tube.

Putting toothpaste back in its tube is often used as an analogy for something irreversible, such as how you can't undo speaking. Megan, however, rejects this assertion and says that you actually ''can'' put toothpaste back in its tube, which is certainly possible in some cases. There are many ways to do this, and none of them are recommendable, but she chooses a particular nasty one where she would blow the paste in her mouth back into the tube. This is obviously much more unsanitary than simply returning unused toothpaste to the tube, which someone might reasonably want to do after squeezing out more than they wanted.

Cueball is so disgusted by this suggestion that he states that Megan's suggestion is actually the worst thing she ever said.

The joke then comes when Megan assumes that Cueball's original analogy still holds, that taking words back is like putting toothpaste back in to the tube. So therefore she ''can'' actually unsay something. She starts to say exactly what Cueball's other friend did "Sorry, I can take it back". But then she continues, and was likely going to say "It's just like - putting toothpaste back in the tube". But Cueball forcefully interrupts her, because the idea of putting toothpaste back in the tube now evokes the distasteful mental image of Megan blowing used toothpaste back into the tube.

Toothpaste is normally loaded into the tube from the back, before it is crimped shut. However, it should ''technically'' be possible to push an extruded amount of paste back in from the front by wrapping one's lips around the whole front of the tube and blowing the paste you have in your mouth back in. This positive pressure can reinflate the tube the same way one blows up a balloon. However, blowing the toothpaste back into the tube would be highly unsanitary, and as the main purpose of toothpaste is to clean teeth, the end result is both counterproductive and disgusting{{citation needed}}. In some cases paste coming out of a tube will be sucked back in if the pressure is released. Such containers would probably be able to suck toothpaste back in, if it was still lying on the toothbrush in one blob (or on the table/in the sink if dropped). As above mentioned this would be unsanitary as germs etc. could get back inside the tube, where the paste is supposed to be clean.

It is common advertising practice to state that a good proportion of relevant experts (typically something like the significant but plausible 8 or 9 out of every 10) support your product or service, such as dentists who recommend your brand of toothpaste - though hopefully only once such a claim is fulfilled. The title text may be echoing this, but in the context of ''dis''satisfaction with Megan's approach (or with [[Randall]] and his ideas, as it is usually he who speaks in the title text. If it refers to Randall him self it is reminiscent of all the [[:Category:Banned from conferences|conferences he has been banned from]]).

It may actually say more about any dental establishment that does ''not'' disapprove of what Megan apparently is not just theorizing about doing.

==Transcript==
:[Cueball, holding his arms out, is talking to Megan.]
:Cueball: I can't believe she said that.
:Cueball: She apologized, but you can't put the toothpaste back in the tube.

:[Megan holds a hand, palm up, out towards Cueball as she replies.]
:Megan: Sure you can; it's easy. You just put your mouth over the opening.

:[Finally they stand straight talking.]
:Cueball: Well, '''''that's''''' the worst thing you've ever said.
:Megan: Sorry, I can take it back. It's just like-
:Cueball: '''''No!'''''

{{comic discussion}}

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

2520: Symbols

2021-09-24T20:36:52Z

108.162.245.245: /* Explanation */ Added title text explanation

{{comic
| number = 2520
| date = September 24, 2021
| title = Symbols
| image = symbols.png
| titletext = "röntgen" and "rem" are 20th-century physics terms that mean "no trespassing."
}}

==Explanation==
{{incomplete|Created by an internet argument - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic discusses different symbols found in equations, and humorously comments on their implications.
*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}}. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*d/dx: An undergrad is working very hard
d/dx is the symbol for a single-variable {{w|Derivative|derivative}} taken with respect to x. This is a mathematical operation that, while difficult, is well within the reach of an undergraduate student, particularly in science. Thus, an equation with this operation would be one that would cause an undergraduate student to work very hard.

*∂/∂x: A grad student is working very hard

;Re
:Reynolds number, used in modelling the flow of fluids. Fluid flow cannot usually be modelled analytically and so a numerical model is necessary.
;(Ta4 - Tb4)
:
;NA
:Avagadro's constant. If you are using this and not working in Moles there is a good chance that you will make a mistake of a factor of a power of ten. THis could create dangerous amounts of chemicals
;µm
:Micrometers are small. Any equipment that is accurate to that degree is likely to be expensive
;mK
:millikelvin are small changes in temperature, or represent very low temperatures. Equipment that uses mK is very expensive
;nm
:Describes the wavelength of laser light
;eV
:describes the energy of a particle beam
;mSv
:The amount of radiation absorbed.
;mg/kg
:The toxicity of a chemical, per kg of body mass. If it is measured in mg/kg it is quite toxic
;µg/kg
:If the chemical is measured in µg/kg it is extremely toxic
;π or τ
:τ = 2π, so it would be easy to make a mistake and use π when τ is correct.

The title text refers to two non-SI units of radiation measurement. An area with significant amounts of radiation is probably dangerous, hence the no trespassing part.

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

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

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

;d/dx
:an undergrad is working very hard
;∂/∂x
:a grad student is working very hard
;ħ
:oh wow, this is apparently a quantum thing
;Re
:someone needs to do a lot of tedious numerical work; hopefully it's not you
;(Ta4 - Tb4)
:you are at risk of skin burns
;NA
:you are probably about to make an incredibly dangerous arithmetic error
;µm
:careful, that equipment is expensive
;mK
:careful, that equipment is very expensive
;nm
:don't shine that in your eye
;eV
:definitely don't shine that in your eye
;mSv
:you are about to get into an internet argument
;mg/kg
:go wash your hands
;µg/kg
:go get in the chemical shower
;π or τ
:whatever answer you get will be wrong by a factor of exactly two

{{comic discussion}}