G4G13 Atlanta Puzzle Talk

I'm posting a link to a talk I gave in Atlanta this spring, on puzzles over the Klein four-group.  It was given at the 13th Gathering for Gardner, a biennial conference devoted to preserving the legacy of  Martin Gardner.

The talk does require a bit of group theory, and also moves quickly because of the tight time constraints.  Unlike most events, every talk occurs in the same room so everyone gets to see every speaker in the conference.  The price is that talks have to be kept very short, but the experience is like nothing you'll find elsewhere.