Hello. Right now I am studying Graphics for my exam X| and I came across complex quaternion fractals (uses 4D complex numbers, link http://local.wasp.uwa.edu.au/~pbourke/fractals/quatjulia/). But that is more or less just a mathematical model used in graphics systems for academical means(e.g. 4-dimensional cubic Mandelbrots). Here u can find some packages, which use quaternion models:rolleyes: http://home.att.net/~Paul.N.Lee/Fractal\_Software.html#QuatPkg Aleš.