I am far from a mathematician, but I remember watching a special on PBS about fractals which I found fascinating. Here is a nice write up on him from the NYTimes. Anyone looking to get into a quant role will run into fractal math sooner or later.
“Dr. Mandelbrot coined the term “fractal” to refer to a new class of mathematical shapes whose uneven contours could mimic the irregularities found in nature.”
Here is the link to the New York Times article.