Dodecadodecahedron

The dodecadodecahedron, or did, is a quasiregular uniform polyhedron. It consists of 12 pentagons and 12 pentagrams, with two of each joining at a vertex. It can be derived as a rectified small stellated dodecahedron or great dodecahedron.

This polyhedron is abstractly regular, being a quotient of the order-4 pentagonal tiling. Among the non-regular uniform polytopes, it shares this property with the ditrigonary dodecadodecahedron. Its realization may also be considered regular if one also counts conjugacies as symmetries.

Vertex coordinates
A dodecadodecahedron of side length 1 has vertex coordinates given by all permutations of and even permutations of
 * $$\left(±1,\,0,\,0\right),$$
 * $$\left(±\frac{1+\sqrt5}{4},\,±\frac{\sqrt5-1}{4},\,±\frac12\right).$$

The first set of vertices corresponds to a scaled octahedron which can be inscribed into the dodecadodecahedron.

Related polyhedra
The dodecadodecahedron is the colonel of a three-member regiment that also includes the small dodecahemicosahedron and the great dodecahemicosahedron.