Lorenz Attractor -- A chaotic 3-dimensional structure related to a set of three nonlinear differential equations associated with fluid dynamics. Plus it's cool to watch. This is a minor tweak of Canthier's excellent 3D version. This one lets you change Rayleigh and Prandtl numbers (check out the Wikipedia entry for Lorenz Attractor for a good summary of what these numbers are). The Scale variable can be used to zoom in or out during drawing. The Rotation can be changed, as can the timestep between points. I've changed it so it plots points, rather than drawing lines. This helps reduce problems with some combinations of parameters and high timesteps.
