Benoît Mandelbrot

He was born in Warsaw, fled the Nazis as a child, studied in Paris, and spent his career at IBM, where in 1980 he used the new computers to draw the picture that now bears his name. He coined the word fractal in 1975. His book argued that clouds are not spheres, mountains are not cones, coastlines are not circles, and that the right language for the geometry of nature is fractal.