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 and 49 vertices.

Vertex coordinates
The vertex coordinates of a great heptagrammic duoprism, centered at the origin and with edge length 2sin(3π/7), are given by:
 * (1, 0, 1, 0),
 * (1, 0, cos(2π/7), ±sin(2π/7)),
 * (1, 0, cos(4π/7), ±sin(4π/7)),
 * (1, 0, cos(6π/7), ±sin(6π/7)),
 * (cos(2π/7), ±sin(2π/7), 1, 0),
 * (cos(2π/7), ±sin(2π/7), cos(2π/7), ±sin(2π/7)),
 * (cos(2π/7), ±sin(2π/7), cos(4π/7), ±sin(4π/7)),
 * (cos(2π/7), ±sin(2π/7), cos(6π/7), ±sin(6π/7)),
 * (cos(4π/7), ±sin(4π/7), 1, 0),
 * (cos(4π/7), ±sin(4π/7), cos(2π/7), ±sin(2π/7)),
 * (cos(4π/7), ±sin(4π/7), cos(4π/7), ±sin(4π/7)),
 * (cos(4π/7), ±sin(4π/7), cos(6π/7), ±sin(6π/7)),
 * (cos(6π/7), ±sin(6π/7), 1, 0),
 * (cos(6π/7), ±sin(6π/7), cos(2π/7), ±sin(2π/7)),
 * (cos(6π/7), ±sin(6π/7), cos(4π/7), ±sin(4π/7)),
 * (cos(6π/7), ±sin(6π/7), cos(6π/7), ±sin(6π/7)).