Heptagrammic antiprismatic prism

The heptagrammic antiprismatic prism or shappip is a prismatic uniform polychoron that consists of 2 heptagrammic antiprisms, 2 heptagrammic prisms, and 14 triangular prisms. Each vertex joins 1 heptagrammic antiprism, 1 heptagrammic prism, and 3 triangular prisms. As the name suggests, it is a prism based on the heptagrammic antiprism. Being a prism based on an orbiform polytope, it is also a segmentochoron.

Vertex coordinates
The vertices of a heptagrammic antiprismatic prism, centered at the origin and with edge length 2sin(2π/7), are given by: where $$H=\sqrt{\frac{1+2\cos\frac{2\pi}7}{2+2\cos\frac{2\pi}7}}\sin\frac{2\pi}7.$$
 * $$\left(1,\,0,\,±H,\,±\sin\frac{2\pi}7\right),$$
 * $$\left(\cos\left(\frac{2\pi}7\right),\,±\sin\left(\frac{2\pi}7\right),\,±H,\,±\sin\frac{2\pi}7\right),$$
 * $$\left(\cos\left(\frac{4\pi}7\right),\,±\sin\left(\frac{4\pi}7\right),\,±H,\,±\sin\frac{2\pi}7\right),$$
 * $$\left(\cos\left(\frac{6\pi}7\right),\,±\sin\left(\frac{6\pi}7\right),\,±H,\,±\sin\frac{2\pi}7\right),$$

Representations
A heptagrammic antiprismatic prism has the following Coxeter diagrams:
 * x2s2s7/2s (full symmetry)
 * x2s2s14/2o
 * xx xo7/2ox&#x (heptagrammic prism atop heptagrammic prism)