Benoit Mandelbrot, the mathematician who is chiefly known for discovering fractals, passed away yesterday at the age of 85.
Mandelbrot's research lay almost entirely outside mainstream research, and his discoveries have had far-reaching consequences. His work on fractals was so revolutionary that, not only did the most famous fractal become his namesake, but it also led to the development of a modern information theory.
In the non-mathematical-but-still-quite-geeky circles, he will probably be best remembered for being the subject of one of Jonathan Coulton's songs (video below). The more mathematical readers may notice that the song actually describes the Julia Set, not the Mandelbrot Set.
And, as everyone on Twitter seems to keep saying, "Thank goodness he wasn't murdered. It would have taken the police forever to draw the chalk outline.".