Triangular-great heptagrammic duoprism

The triangular-great heptagrammic duoprism, also known as the 3-7/3 duoprism, is a uniform duoprism that consists of 3 great heptagrammic prism s and 7 triangular prism s, of which two of each meet at each vertex.

Coordinates
The coordinates of a triangular-great heptagrammic duoprism, centered at the origin and with edge length 2sin(3π/7), are given by:


 * (0, 2sin(3π/7)*√3/3, 1, 0),
 * (0, 2sin(3π/7)*√3/3, cos(2π/7), ±sin(2π/7)),
 * (0, 2sin(3π/7)*√3/3, cos(4π/7), ±sin(4π/7)),
 * (0, 2sin(3π/7)*√3/3, cos(6π/7), ±sin(6π/7)),
 * (±sin(3π/7), –sin(3π/7)*√3/3, 1, 0),
 * (±sin(3π/7), –sin(3π/7)*√3/3, cos(2π/7), ±sin(2π/7)),
 * (±sin(3π/7), –sin(3π/7)*√3/3, cos(4π/7), ±sin(4π/7)),
 * (±sin(3π/7), –sin(3π/7)*√3/3, cos(6π/7), ±sin(6π/7)).