Julia fractal Computer graphic showing a three dimensional spiral fractal image derived from the Julia Set The Julia Set is a class of shapes plotted from complex number coordinates Each point is assigned a colour depending upon its behaviour under a series of simple but repeated mathe matical operations or mappings The Julia Set was invented and studied during World War I by the French mathematicians Gaston Julia and Pierre Fatou The betterknown Mandelbrot Set arose as a result of attempts made by the mathematician Benoit Mandelbrot in the s to rationalize the massive variety of forms of the Julia Set