Can you cut a hole in a 3x5 card that's large enough to crawl through? Topological trickery and some other classic science experiments.
posted by Wolfdog on Jul 2, 2007 - 40 comments

Bending a soccer ball - mathematically. Found via Ivars Peterson's short exposition on Braungardt and Kotschick's The Classification of Football Patterns [pdf, technical].
posted by Wolfdog on Aug 17, 2006 - 18 comments