In and of itself, well, it may be unimpressive. Fine. Mathematics, after all, is nothing if not the study of tautologies (interesting tautologies, if you ask me). But then there's this page, which has a whopping eighty-one proofs! They range from simple to "Damn it, I need to take more math courses" in complexity.
What I find so cool about this is that so many cultures have arrived at the conclusion independently. As geometry is simply formal logic about numbers and their relations, I think it could be used as a rough measure of intellectual sophistication (give or take a whole bunch of whatever, of course). Consider, for example, the following image:
I can't read that. It's fuckin' Chinese to me, man. But I sure as Hell know what it means! Mathematics, truly, is the Universal language - and geometric proofs are perhaps the only ideas that could in any sense at all be flawlessly translated between languages.