Since I wrote that comment I feel the itch to do it myself :) He said topology, but I don't think he meant what I'm thinking of: a torus! A Mobius band! The pro

Since I wrote that comment I feel the itch to do it myself :) He said topology, but I don't think he meant what I'm thinking of: a torus! A Mobius band! The projective plane! My curiosity is getting the better of me.