This has been haunting me for weeks now.
It is easy to divide a rectangle to eight (not necessarily identical) convex pentagons. It seems to be impossible to do with less (playing around makes this apparent). However, though I've tried for several hours on multiple occasions, I can come up with neither a proof nor a counterexample. Any thoughts? Ideas?
Eight is minimal. This question has been asked and answered on the Puzzling StackExchange.
Is it possible to divide a square into convex pentagons?