21/7/2006

Limerick

Filed under: — Bravus @ 10:22 am

There’s a bit of a limerick thread going on on the William Gibson Board at the moment. Most of my contributions have related to particular things or people on the board, so they don’t stand alone very well, but I thought this one was kinda fun:

The secret to limerick’s metre
Is to make every line even sweeter
Doesn’t matter how long
All that counts is the song
But \/\/r171n6 1|\| d16i72 1z 13373R

180/360

Filed under: — Bravus @ 9:35 am

If we drive home from Brisbane via the freeway, there’s one point on our journey home where we approach a roundabout (traffic circle), go around it and come back, going the opposite direction on the same road we came in on.

Sue said this meant we were ‘doing a 360’, and I said ‘no, it’s a 180’. Significant discussion ensued…

My argument was that you go in one way, and come out facing in exactly the opposite direction, having rotated through 180o. As a good physicist, I argued that the circle you drive around on the roundabout is irrelevant – what’s important is the initial and final states. I said that to do a 360 you’d have to keep on going around the roundabout until you were going the same way you’d been going initially.

Sue said ‘No, if you took the left turnoff you’d have turned 90o from your initial direction, if you went straight ahead that’s 180, taking your initial position as 0, if you went around and turned right you’d have gone through 270 and going right around to come back the way you came is a 360. (I’ve helpfully illustrated the situation and her system below.)

180

I think her system of descriptions has a lot to recommend it as a way of explaining directions to people… but it seems to me as though under that system, when you’re driving along a straight stretch of road you’re continually doing 180s, and that doesn’t seem right. So I still reckon we do a 180 at the roundabout. What do you think?