The greatest geometer of the 20th century, Harold Scott MacDonald Coxeter, has died (obituary). He was a math uber-geek, with connections to an amazing list of other luminaries, including Bertrand Russell, Wittgenstein, and Escher.

I first heard of Coxeter as one of the authors of The 59 Icosahedra, which sounds like a Hitchcock movie, but is actually a treatise on the stellations of the icosahedron. The image below is a diagram of the stellation face of the icosahedron (more information and pictures here).

He contributed authoritatively to all areas of geometry, from introductory textbooks to expositions on non-Euclidean geometery, to his specialty, extending the concepts of uniform polyhedra to higher dimensions.

As an example of his old-school style, he apparently never used computers, writing his papers in pencil. Just being a professional geometer interested in shapes made him seem like a throwback. Whenever I try to catch a whiff of what recent geometry work is like, it seems more like complex algebra or number theory than actual geometry (aren’t there supposed to be shapes in there somewhere?).