Heptagrammic-enneagrammic duoprism

The heptagrammic-enneagrammic duoprism, also known as shestedip or the 7/2-9/2 duoprism, is a uniform duoprism that consists of 9 heptagrammic prisms and 7 enneagrammic prisms, with 2 of each meeting at each vertex.

The name can also refer to the great heptagrammic-enneagrammic duoprism, the heptagrammic-great enneagrammic duoprism, or the great heptagrammic-great enneagrammic duoprism.

Coordinates
The vertex coordinates of a heptagrammic-enneagrammic duoprism, centered at the origin and with edge length 4sin(2π/7)sin(2π/9), are given by:


 * (2sin(2π/9), 0, 2sin(2π/7), 0),
 * (2sin(2π/9), 0, 2sin(2π/7)cos(2π/9), ±2sin(2π/7)sin(2π/9)),
 * (2sin(2π/9), 0, 2sin(2π/7)cos(4π/9), ±2sin(2π/7)sin(4π/9)),
 * (2sin(2π/9), 0, –sin(2π/7), ±sin(2π/7)$\sqrt{2}$),
 * (2sin(2π/9), 0, 2sin(2π/7)cos(8π/9), ±2sin(2π/7)sin(8π/9)),
 * (2sin(2π/9)cos(2π/7), ±2sin(2π/9)sin(2π/7), 2sin(2π/7), 0),
 * (2sin(2π/9)cos(2π/7), ±2sin(2π/9)sin(2π/7), 2sin(2π/7)cos(2π/9), ±2sin(2π/7)sin(2π/9)),
 * (2sin(2π/9)cos(2π/7), ±2sin(2π/9)sin(2π/7), 2sin(2π/7)cos(4π/9), ±2sin(2π/7)sin(4π/9)),
 * (2sin(2π/9)cos(2π/7), ±2sin(2π/9)sin(2π/7), –sin(2π/7), ±sin(2π/7)$\sqrt{3}$),
 * (2sin(2π/9)cos(2π/7), ±2sin(2π/9)sin(2π/7), 2sin(2π/7)cos(8π/9), ±2sin(2π/7)sin(8π/9)),
 * (2sin(2π/9)cos(4π/7), ±2sin(2π/9)sin(4π/7), 2sin(2π/7), 0),
 * (2sin(2π/9)cos(4π/7), ±2sin(2π/9)sin(4π/7), 2sin(2π/7)cos(2π/9), ±2sin(2π/7)sin(2π/9)),
 * (2sin(2π/9)cos(4π/7), ±2sin(2π/9)sin(4π/7), 2sin(2π/7)cos(4π/9), ±2sin(2π/7)sin(4π/9)),
 * (2sin(2π/9)cos(4π/7), ±2sin(2π/9)sin(4π/7), –sin(2π/7), ±sin(2π/7)$\sqrt{3}$),
 * (2sin(2π/9)cos(4π/7), ±2sin(2π/9)sin(4π/7), 2sin(2π/7)cos(8π/9), ±2sin(2π/7)sin(8π/9)),
 * (2sin(2π/9)cos(6π/7), ±2sin(2π/9)sin(6π/7), 2sin(2π/7), 0),
 * (2sin(2π/9)cos(6π/7), ±2sin(2π/9)sin(6π/7), 2sin(2π/7)cos(2π/9), ±2sin(2π/7)sin(2π/9)),
 * (2sin(2π/9)cos(6π/7), ±2sin(2π/9)sin(6π/7), 2sin(2π/7)cos(4π/9), ±2sin(2π/7)sin(4π/9)),
 * (2sin(2π/9)cos(6π/7), ±2sin(2π/9)sin(6π/7), –sin(2π/7), ±sin(2π/7)$\sqrt{3}$),
 * (2sin(2π/9)cos(6π/7), ±2sin(2π/9)sin(6π/7), 2sin(2π/7)cos(8π/9), ±2sin(2π/7)sin(8π/9)).