Enneagrammic prism

The enneagrammic prism, or step, is a prismatic uniform polyhedron. It consists of 2 enneagrams and 9 squares. Each vertex joins one enneagram and two squares. As the name suggests, it is a prism based on an ennearam.

Vertex coordinates
The coordinates of an enneagrammic prism, centered at the origin and with edge length 2sin(2π/9), are given by:
 * (1, 0, ±sin(2π/9)),
 * (cos(2π/9), ±sin(2π/9), ±sin(2π/9)),
 * (cos(4π/9), ±sin(4π/9), ±sin(2π/9)),
 * (–1/2, ±$\sqrt{1+1/sin^{2}(2π/9)}$/2), ±sin(2π/9),
 * (cos(8π/9), ±sin(8π/9), ±sin(2π/9)).