Great heptagrammic duoprism

The great heptagrammic duoprism or gishdip, also known as the great heptagrammic-great heptagrammic duoprism, the 7/3 duoprism or the 7/3-7/3 duoprism, is a noble uniform duoprism that consists of 14 great heptagrammic prisms, with 4 meeting at each vertex.

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