Explain xkcd: It's 'cause you're dumb.
The comic presents a flyer with text typical of a ubiquitous advertisement for a "Weight Loss Program". However, the image at the bottom of the flyer and the title text make it clear that the flyer is actually an advertisement for a trebuchet club. This unexpected meaning is meant to highlight the ambiguity of the flyer's content.
A trebuchet is gravity powered siege engine, which was originally used to attack fortifications. It works by dropping a raised counter weight to rotate a throwing arm, launching a projectile on a ballistic path.
The phrase "We'll help you hit your target by dropping 30 pounds FAST" is where the ambiguity is produced. In the context of a weight loss ad, the "target" would be a rhetorical device referring to the weight which one wishes to achieve. In the context of a trebuchet club, the target is a literal location which one is trying to hit with a projectile. Likewise, a weight loss ad may indicate that a client could quickly lose 30 pounds (~13,6 kg). However, in this context, the 30 pounds being dropped is either the counter-weight - which is dropped to provide a trebuchet with its power, implying a rather small trebuchet - or the projectile itself being dropped at the target - it will be slower than the counter-weight but definitely still much faster than any weight loss program.
The only hint that the flyer advertises a trebuchet club is in the drawing at the bottom of the flyer, which appears to show two individuals pondering a ballistic path towards a castle tower (though no trebuchet is shown). The subtitle indicates that this flyer "may have been too subtle", while the title text suggests that, if the flyer is indeed too subtle a form of advertisement, they have less subtle options of announcing their club's existence — such as using their trebuchet to attack the town.
- [We see a poster taped to a wall. It has Megan and Cueball in the bottom left, a silhouetted crenellated tower in the bottom right, and a thin arc between them. It reads:]
- Struggling with those 2013 resolutions?
- We'll help you hit your target
- By dropping thirty pounds fast
- [Small print.]
- WEB: http: [illegible].com
- CALL: (555) 123-4567
add a comment!
- The flyer for our trebuchet–building club may have been too subtle.
"Dropping Thirty Pounds Fast"? Is that a reference to the projectile weight being approx 30lb and "dropping" it on someone's walls? DD (talk) 10:03, 14 January 2013 (UTC)
- I was thinking more along the lines of thirty pounds of blood and dismembered flesh. Davidy22[talk] 10:46, 14 January 2013 (UTC)
A trebuchet works by dropping a large weight connected to the swing arm, thereby propelling the projectile in a parabola (hopefully) towards the target. Thus, by dropping 30 lbs fast, you may literally hit your target. 188.8.131.52 (talk) (please sign your comments with ~~~~)
- Anyhow the explanation is a little off. The "subtlety" referred to is not that people tend to ignore weight loss flyers. It is that the flyer looks like a flyer for a weight loss programme, while it is actually trying to recruit people for something entirely different. Most people would not get this and sign up thinking that they would lose body weight, while they would be signing up for the trebuchet club. The only hint is the drawing, really. I agree with the above comment that the "dropping 30lbs" probably refers to the projectile. 184.108.40.206 10:52, 14 January 2013 (UTC)
- Actually - I didn't mean that the 30lbs was the projectile but rather the counterweight propelling the projectile. 220.127.116.11 12:53, 14 January 2013 (UTC)
My vote is that 30lbs stands for the projectile. 18.104.22.168 15:55, 14 January 2013 (UTC)
30lbs for the projectile is most consistent with the alt-text, which implies that they will be hurling projectiles at the town. A 30lbs counterweight would only be able to fling a projectile an order of magnitude smaller. Also, for medieval trebuchets the "average mass of the projectiles was probably around 50–100 kg" (Wikipedia article) --Forlackofabettername (talk) 16:23, 14 January 2013 (UTC)
- A trebuchet club would likely be building smaller models than the original medieval ones, so my vote is the 30lbs is referring to the counterweight, not the projectile. In a trebuchet, the counterweight drops fast, whereas the projectile doesn't initially drop at all, but it rather launches upwards and sideways; it'll be some time before it starts dropping, and even then not very quickly as the vertical speed takes some time to switch from up to zero, and then finally down, eventually building up speed to something that might be considered "FAST". But the "FAST" is mostly in the horizontal direction rather than seen as a "drop". In the meantime, that counterweight had already dropped more directly a long time ago. --boB
- Even the projectiles will take more to drop, it still quite "FAST" compare any weight loss program, so I think it can still refer to the projectile. Arifsaha (talk) 18:17, 14 January 2013 (UTC)
- I can just imagine someone from the club saying "Let's drop 30 lbs on the target". Besides, I'd consider the usage of the word "drop" to be more metaphorical because in the operation of a trebuchet, no individual actually drops a counterweight; they simply pull a pin or cut a rope. 22.214.171.124 20:54, 14 January 2013 (UTC)
A what-if wonder: considering a trebuchet is a weapon, will it be legal to own and place a trebuchet in your own backyard? Arifsaha (talk) 18:20, 14 January 2013 (UTC)
- The art of backyard ballistics is a firmly established niche hobby -- presumably for people with really big backyards. --Prooffreader (talk) 20:22, 14 January 2013 (UTC)
- Presumably people with really big backyards ... or with really annoying neighbors. 126.96.36.199 (talk) (please sign your comments with ~~~~)
- I needed a new hobby since I broke the last one... this is a contender! Thanks! :D DD (talk) 16:42, 15 January 2013 (UTC)
This might be example of literal vs figurative meaning: for trebuchet it is literally dropping counterweight and literally hitting a target. --JakubNarebski (talk) 17:06, 15 January 2013 (UTC)
Thanks for finally turning my temporary text into a proper explanation :) 188.8.131.52 17:16, 15 January 2013 (UTC)
Image could also be mistaken for two people taking a walk by a hill to a castle; which would be consistent with mistaking the add for one for weight-loss; The absence of any trebuchet in the picture suggests this is deliberate. 184.108.40.206 10:04, 16 January 2013 (UTC)
Although there is ambiguity here, I would think that the 30 pounds is referring to the counterweight. This is due to the fact that any device can hurl a projectile (spring catapult, torsion device, and of course trebuchet) but what sets the trebuchet apart from the rest is that it is powered by falling mass. Also, any trebuchet club that is just starting will likely be building small golfball trebuchets which would likely use counterweights on the scale of 30 pounds. I agree the alt-text makes more sense if they are actually hurling 30 pounds, but I think the main joke here is the comic that makes use of the fact that a trebuchet is literally a dropping weight. Lastly, you aren't "dropping" the projectile, you are hurling it. 220.127.116.11 (talk) (please sign your comments with ~~~~)
- Of course it's truly pedantic, but has anybody considered that dropping a 30-pound counterweight to fling a projectile imparts the same amount of energy1 to the target as dropping a 30-pound "projectile" (which would be more like a bomb in this case) on the target from roughly the same height the counterweight drops? So dropping a 30-pound counterweight on a trebuchet is very much indeed like dropping a 30-pound payload directly on your target, albeit at an angle that's more likely to be disadvantageous to the target, and from a location that's generally easier to occupy.
- 1This is disregarding the additional friction losses, of course, which would be higher in the case of flinging a projectile with a trebuchet than in the case of dropping a bomb, due to friction in the trebuchet's axle or other mechanisms, the greater distance the projectile most likely travels as well as the higher speed with which it does so, and the projectile's lower mass and thus lower inertia. Daddy (talk) 14:01, 17 April 2013 (UTC)
But what IS the LEAST subtle method???18.104.22.168 20:40, 17 January 2013 (UTC)
I'm surprised that nobody else has mentioned (or that I have somehow managed to skim over) the reference to the usual over-figerative depiction of "hitting a target" in such aspirationally motivating advertising, i.e. an archery target with an arrow in the bullseye. Or unpierced, but pensively awaiting the projectile, depicted in flight (in extreme perspective, heading intothe page that the target often faces straight out from) or otherwise. (I suspect that the phenomena extends to firearms targets as well, especially in communities with a relatively high amount of target-shooting involvement. I'm sure I've seen the old "german soldier silhouette" image used, albeit very rarely.) But, anyway, I can imagine that Randall is additionally riffing off the number of "Hit your target!" flyers with a bullseye motif... but skewing that to the fictional target reader's expectation that a motif or depiction of a parabolic trajectory might be supposed to convey exactly the same thing, rather than its actual literalist meaning. 22.214.171.124 00:44, 29 March 2013 (UTC)
I'm impressed that nobody added to the explanation how much is 30 pounds in kilograms. I did that now. 126.96.36.199
00:18, 16 February 2014 (UTC)