Mandelbrot fractal. Computer-generated fractal derived from the Mandelbrot Set. Fractal geometry is used to derive complex shapes as are often found in nature. The Mandelbrot Set, named after the mathematician Benoit B. Mandelbrot, is a group of complex numbers plotted using their real and imaginary parts as coordinates. Complex patterns are produced by a series of repeated mathematical operations or mappings. Fractals are used to create models for real-world non-linear phenomena such as stock market prices, plant growth, the erosion of coastlines and fluid turbulence.