Pi Keychain / Backpack Charm

I made this pi keychain (or backpack charm) for my somewhat geeky son so he could attach it to his backpack for school.

I started out with Garamond bold, then rounded the upper right-hand corner, and punched out a hole. I eyeballed it all, but it turned out to be just about the same size as the Turtle Keychain by Roland ( http://www.thingiverse.com/thing:23823 ), which I printed at the same time for my equally-geeky-but-in-a-totally-different-way girl.