Other geometric primitives can be used instead of spheres. This PovRay scene file waterman2.pov will create such forms, indeed it can be easily modified to include any PovRay object [Update: a modified/extended version created by Steve Waterman (March 2006) polyhedra.zip]. The original version supports the platonic solids, you will need the following files: cube.pov, octahedron.pov, dodecahedron.pov, icosahedron.pov, and tetrahedron.pov.
Even other Waterman polyhedra can be used instead of spheres. This PovRay file (waterman3.pov) constructs these. For a list of sphere and polyhedra models in PovRay format that can be used with this file, see the first 50 roots in this directory.
A good sense of the radial distribution can be illustrated by varying the colour as a function of radius.
