14-2 step prism

The 14-2 step prism is a convex isogonal polychoron and a member of the step prism family. It has 7 rhombic disphenoids and 70 phyllic disphenoids of five kinds as cells, with 22 (2 rhombic and 20 phyllic disphenoids) joining at each vertex.

Vertex coordinates
Coordinates for the vertices of a 14-2 step prism inscribed in a tetradecagonal duoprism with base lengths a and b are given by: where k is an integer from 0 to 13. If the edge length differences are to be minimized, the ratio of a:b must be equivalent to 1:$$1+2\cos\frac{2\pi}{7}$$ ≈ 1:2.24698.
 * (a*sin(πk/7), a*cos(πk/7), b*sin(2πk/7), b*cos(2πk/7)),