I want to divide the surface of a donut into as many different regions as possible. The regions can be any shape, as long as they are each in one piece. Each region must touch each of the other regions (touching on a corner doesn't count). How many regions can I make?

(In reply to re: easy way to 7 by Hugo)

Sorry, it's completely wrong. I was travelliing after post it and couldn't repair.

Posted by armando on 2005-05-01 12:47:33