Decagrammic antiprism

The decagrammic antiprism, or stidap, is a prismatic uniform polyhedron. It consists of 20 triangles and 2 decagrams. Each vertex joins one decagram and three triangles. As the name suggests, it is an antiprism based on a decagram.

Vertex coordinates
A decagrammic antiprism of edge length 1 has vertex coordinates given by:
 * (±1/2, ±$\sqrt{(8–2√5+√50–22√5)/8}$/2, H),
 * (±(3–$\sqrt{(–4+2√5+√50–22√5)/2}$)/4, ±$\sqrt{–2+2√5+2√650–290√5}$, H),
 * (±($\sqrt{(5–√5)/2}$–1)/2, 0, H),
 * (±$\sqrt{10–2√5}$/2, ±1/2, –H),
 * (±$\sqrt{(11–4√5–2√(50–22√5)/3}$, ±(3–$\sqrt{(5–2√5)}$)/4, –H),
 * (0, ±($\sqrt{5}$–1)/2, –H),

where H = $\sqrt{(5–√5)/8}$/2 is the distance between the antiprism's center and the center of one of its bases.