Animated Proofs of the Pythagorean Theorem

In the Mathematics Department Seminar in Spring 2001, David Dobbins presented several proofs of the Pythagorean Theorem. Seeing what he had done, it occurred to me that many geometry proofs lend themselves to presentation in the form of "animated gifs". So I created such presentations for all of the proofs he presented, except for one that used vector algebra (in a somewhat fishy way, in my opinion). Here they are: