# I don't quite get today's xkcd strip.
**URL:** https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596
**Category:** Cafe Society
**Created:** [October 3, 2012, 4:34pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596 "2012-10-03T16:34:54Z")
**Posts on this page:** 19
**Page:** 1
### Author:  [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)
#### Post date: [October 3, 2012, 4:34pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/1 "2012-10-03T16:34:54Z")
> **[Traffic Lights](https://xkcd.com/1116/)**
>
> There's an intersection I drive through sometimes that has a forward green arrow, a red light, and a 'no turns' sign all on one pole. I honestly have no idea what it's telling me to do.
Eh? Is there some hidden math/coding joke here?
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### Author:  [@kayaker](https://boards.straightdope.com/u/kayaker)
#### Post date: [October 3, 2012, 4:37pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/2 "2012-10-03T16:37:14Z")
Unless I missed something, I just thought it laughing at overly/needlessly complicated intersections. (so what did I miss?)
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### Author:  [@phreesh](https://boards.straightdope.com/u/phreesh)
#### Post date: [October 3, 2012, 4:38pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/3 "2012-10-03T16:38:49Z")
I also don’t 100% follow it, but it appears to be an ‘impossible’ intersection. I haven’t bothered to follow the logiic all the way through, but I assume it looks like a typical intersection, but when you follow the sigsn/lights, you actually can’t move.
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### Author:  [@Simplicio](https://boards.straightdope.com/u/Simplicio)
#### Post date: [October 3, 2012, 4:45pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/4 "2012-10-03T16:45:29Z")
Yea, the joke is just how conveluted it is. If you watch for a while, one light has two green arrows pointing in the same direction. One has the red-light in the middle, one has a purple light. There are forward and backword arrows and some lights show red and yellow at the same time.
I get the complaint. There’s a busy intersection I cross for work everyday where the roads meet at a weird angle and the lights aren’t lined up with their corresponding lanes very well. The green arrow thing in one lane looks like a green light for the other lane, with the result being that motorists are constantly accidentally running the red light and almost (and in at least one case, actually) hitting pedestrians. Called the city twice to complain, but nothings changed.
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### Author:  [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)
#### Post date: [October 3, 2012, 4:49pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/5 "2012-10-03T16:49:06Z")
At first I thought it was possible, but convoluted to the point of absurdity. Right turns are from the left lane, and left turns are from the right lane; that works if only one has a green light at a time. But it quickly becomes impossible.
I’m pretty sure the guy who draws xkcd is somewhere around my neighborhood. I wonder if I could find the intersection described in the mouseover.
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### Author:  [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)
#### Post date: [October 3, 2012, 5:52pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/6 "2012-10-03T17:52:46Z")
> [@phreesh](#):
>
> I also don’t 100% follow it, but it appears to be an ‘impossible’ intersection. I haven’t bothered to follow the logiic all the way through, but I assume it looks like a typical intersection, but when you follow the sigsn/lights, you actually can’t move.
Yeah, the light arrangement and phasing are nonsensical. The purple light made me laugh. I’m surprised he didn’t include one of those harizontally mounted lights as well.
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### Author:  [@standingwave](https://boards.straightdope.com/u/standingwave)
#### Post date: [October 3, 2012, 5:57pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/7 "2012-10-03T17:57:30Z")
> [@kayaker](#):
>
> Unless I missed something, I just thought it laughing at overly/needlessly complicated intersections. (so what did I miss?)
This. Alt Text:_“There’s an intersection I drive through sometimes that has a forward green arrow, a red light, and a ‘no turns’ sign all on one pole. I honestly have no idea what it’s telling me to do.”_
Jim: Pssssttt… what does the yellow light mean?
Bobby: “Slow down.”
Jim: What… does… the… yellow… light… mean?
Bobby: “Slow down!”
"Jim: Whaaaat… dooooeeees… theeeee… yeeeel-looowwww… liiiiight… meeeeaaan?
😃
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### Author:  [@Pashnish\_Ewing](https://boards.straightdope.com/u/Pashnish_Ewing)
#### Post date: [October 3, 2012, 6:53pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/8 "2012-10-03T18:53:22Z")
I think the joke is that the longer you stay on the comic, the more absurd it becomes (Up/down arrows, the purple light, simultaneous red/green on the same light).
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### Author:  [@Quercus](https://boards.straightdope.com/u/Quercus)
#### Post date: [October 3, 2012, 7:20pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/9 "2012-10-03T19:20:11Z")
Was I the only one who wondered, at least briefly, if there was some message encoded in the flashing lights, if one treated them as a bit pattern encoding 7-bit ASCII or something?
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### Author:  [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)
#### Post date: [October 3, 2012, 7:22pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/10 "2012-10-03T19:22:58Z")
The yellow light means “drive like hell, because the light is about to turn red.”
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### Author:  [@Strassia](https://boards.straightdope.com/u/Strassia)
#### Post date: [October 3, 2012, 8:04pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/11 "2012-10-03T20:04:17Z")
The signs (except for the one on the far left that precludes any forward motion) are actually not that improbable. There is an intersection near me where a one way street and a two way street merge. The resulting traffic light set is, going left to to right, left only, left/straight, right/straight, right only, left only, right straight. Add a third street coming in on the left side and it could almost be what you see here.
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### Author:  [@chacoguy](https://boards.straightdope.com/u/chacoguy)
#### Post date: [October 3, 2012, 9:14pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/12 "2012-10-03T21:14:23Z")
I think the ‘purple’ light is supposed to be blue as a nod to Jimi Hendrix.
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### Author:  [@Peanuthead](https://boards.straightdope.com/u/Peanuthead)
#### Post date: [October 3, 2012, 10:36pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/13 "2012-10-03T22:36:22Z")
If you have to work that hard, forget about it. It’s not worth the srtuggle for a chuckle. And from what I’ve seen from this comic strip, a mild chuckle is about the most I’ve ever gotten from it.
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### Author:  [@Suburban\_Plankton](https://boards.straightdope.com/u/Suburban_Plankton)
#### Post date: [October 3, 2012, 10:39pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/14 "2012-10-03T22:39:28Z")
> [@carnivorousplant](#):
>
> The yellow light means “drive like hell, because the light is about to turn red.”
“Red light, stop
green light, go
yellow light, go…very fast”
[Starman](http://www.youtube.com/watch?v=6NEFYCaKakE)
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [October 3, 2012, 10:45pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/15 "2012-10-03T22:45:48Z")
> [@](#):
>
> If you have to work that hard, forget about it. It’s not worth the srtuggle for a chuckle. And from what I’ve seen from this comic strip, a mild chuckle is about the most I’ve ever gotten from it.
OK, then, don’t read it. I’m sure there are comics you like that I don’t, too. But many of us here _do_ get more than a chuckle from it, and I for one got the point of this one immediately.
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### Author:  [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)
#### Post date: [October 3, 2012, 11:12pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/16 "2012-10-03T23:12:19Z")
I’ve seen intersections like this in Chicago where diagonal roads slash their way through the otherwise sensible street grid, and there are multiple “Obey your signal only” signs along with stacked double reds, circles and arrows and a paragraph on the back of each one.
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### Author:  [@Flander](https://boards.straightdope.com/u/Flander)
#### Post date: [October 3, 2012, 11:39pm UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/17 "2012-10-03T23:39:18Z")
hehe…purple light.
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### Author:  [@SCAdian](https://boards.straightdope.com/u/SCAdian)
#### Post date: [October 4, 2012, 1:11am UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/18 "2012-10-04T01:11:05Z")
A blogger I read posted some pictures a couple years back - photos he’d taken at an intersection somewhere in California. The left lane had a right-turn arrow, and the right lane had a left-turn arrow - both green at the same time, so cars would be turning into one another. And at another point in the cycle, one light had a straight-ahead arrow, directing traffic across the T-intersection into a brick wall…
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### Author:  [@PlainJain](https://boards.straightdope.com/u/PlainJain)
#### Post date: [October 4, 2012, 3:03am UTC](https://boards.straightdope.com/t/i-dont-quite-get-todays-xkcd-strip/636596/19 "2012-10-04T03:03:54Z")
> [@Quercus](#):
>
> Was I the only one who wondered, at least briefly, if there was some message encoded in the flashing lights, if one treated them as a bit pattern encoding 7-bit ASCII or something?
No, it was actually my first thought.