In a Feynman book, he talks about a man (I believe he lived 400-500 years ago) that discovered something about the dimensions of triangles (I think)by hanging a chain around the triangle. I've searched in "Six Not So Easy Pieces" but haven't been able to find it.
I'm trying to find the name of this man; it would be great if someone remembers this (or know whom I'm talking about off the top of their head).