Benoit Mandelbrot (1924-2010), French-American mathematician. Mandelbrot is best known as the father of fractal geometry, a branch of complex number theory. Mandelbrot coined the term fractal in 1975, which he defined as ‘a rough or fragmented geometric shape that can be split into parts, each of which is (at least approximately) a reduced-size copy of the whole’.

Credit: PHILIPPE GONTIER / LOOK AT SCIENCES / SCIENCE PHOTO LIBRARY