Great heptagrammic retroprismatic prism

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

Vertex coordinates
The vertices of a great heptagrammic retroprismatic prism, centered at the origin and with edge length 2sin(3π/7), are given by: where $$H=\sqrt{\frac{1-2\cos\frac{3\pi}7}{2-2\cos\frac{3\pi}7}}\sin\frac{3\pi}7.$$
 * $$\left(1,\,0,\,±H,\,±\sin\frac{3\pi}7\right),$$
 * $$\left(\cos\left(\frac{2\pi}7\right),\,±\sin\left(\frac{2\pi}7\right),\,±H,\,±\sin\frac{3\pi}7\right),$$
 * $$\left(\cos\left(\frac{4\pi}7\right),\,±\sin\left(\frac{4\pi}7\right),\,±H,\,±\sin\frac{3\pi}7\right),$$
 * $$\left(\cos\left(\frac{6\pi}7\right),\,±\sin\left(\frac{6\pi}7\right),\,±H,\,±\sin\frac{3\pi}7\right),$$

Representations
A great heptagrammic retroprismatic prism has the following Coxeter diagrams:
 * x2s2s7/4s (full symmetry)
 * x2s2s14/4o
 * xx xo7/4ox&#x (great heptagrammic prism atop great heptagrammic prism)