Great Stellated Dodecahedron plus Great Icosahedron
This model is a compound of the
great stellated dodecahedron and its dual, the
great icosahedron, both
The model is also a stellation of the
Great Icosidodecahedron. All compounds of
regular polyhedra and their duals display pairs of edges which bisect each
other at right angles. You can see places where some edges intersect others at
right angles, but those are additional occurrences and not bisecting. The ones
which bisect, and occur between dual edges, occur out of sight. Look half way
along one of the long pentagram edges, or half way along one of the shorter
triangle edges and you'll see where it's hiding, beneath the concave
intersection of two pentagrams. If the great icosahedron where any larger, it
would start to show at those points.
This model has a diameter just under 12cm.