Icosahedron

A parametric icosahedron made with OpenSCAD's polyhedron() function. It is more an exercise in math. Probably not printable for a variety of reasons (overhangs, probably hollow).

Taken from: http://en.wikipedia.org/wiki/Icosahedron#Cartesian_coordinates

If you want a solid (read "working") one, try: http://www.thingiverse.com/thing:65709

If you want a mathematical model of the icosahedron, download away.