High Quality Content by WIKIPEDIA articles! Benoit B. Mandelbrot (20 November 1924 – 14 October 2010) was a Polish-born, French and American mathematician, noted for developing a "theory of roughness" in nature and the field of fractal geometry to help prove it, which included coining the word "fractal." He later created the Mandelbrot set of intricate, never-ending fractal shapes, named in his honor.