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xkcd #2842: Inspiraling Roundabout
(imgs.xkcd.com)
Alt text:
Look, I just think we need to stop coddling those hedonistic roundabout hogs who get into the inner lane and circle for hours, wasting valuable capacity.
The lines are dotted. You can cross dotted lines. If you do cross a dotted line, please check your mirrors, or you might run into the point of the comic.