Out of the blue, DS10 decided to develop a proof for the Pythagorean theorem last night before bed. And after about 20 minutes he developed one that was very elegant. While I have encouraged his math ability, I never taught him any proofs so I'm not quite sure where he picked it up.

It wasn't a unique proof as I learned later from an Internet search, but it was his original work. For those that are interested, it is quite similar to Proof #4 on the following page: //www.cut-the-knot.org/pythagoras/index.shtml