Enneagonal prism

The enneagonal prism, or ep, is a prismatic uniform polyhedron. It consists of 2 enneagons and 9 squares. Each vertex joins one enneagon and two squares. As the name suggests, it is a prism based on an enneagon.

Vertex coordinates
The coordinates of an enneagonal prism, centered at the origin and with edge length 2sin(π/9), are given by:
 * $$\left(1,\,0,\,±\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{2\pi}{9}\right),\,±\sin\left(\frac{2\pi}{9}\right),\,±\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{4\pi}{9}\right),\,±\sin\left(\frac{4\pi}{9}\right),\,±\sin\frac\pi9\right),$$
 * $$\left(-\frac12,\,±\frac{\sqrt3}{2},\,±\sin\frac\pi9\right),$$
 * $$\left(\cos\left(\frac{8\pi}{9}\right),\,±\sin\left(\frac{8\pi}{9}\right),\,±\sin\frac\pi9\right).$$