Enneagonal-great enneagrammic duoprism

The enneagonal-great enneagrammic duoprism, also known as egstedip or the 9-9/4 duoprism, is a uniform duoprism that consists of 9 enneagonal prisms and 9 great enneagrammic prisms, with 2 of each meeting at each vertex.

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


 * (2sin(4π/9), 0, 2sin(π/9), 0),
 * (2sin(4π/9), 0, 2sin(π/9)cos(2π/9), ±2sin(π/9)sin(2π/9)),
 * (2sin(4π/9), 0, 2sin(π/9)cos(4π/9), ±2sin(π/9)sin(4π/9)),
 * (2sin(4π/9), 0, –sin(π/9), ±sin(π/9)$\sqrt{2}$),
 * (2sin(4π/9), 0, 2sin(π/9)cos(8π/9), ±2sin(π/9)sin(8π/9)),
 * (2sin(4π/9)cos(2π/9), ±2sin(4π/9)sin(2π/9), 2sin(π/9), 0),
 * (2sin(4π/9)cos(2π/9), ±2sin(4π/9)sin(2π/9), 2sin(π/9)cos(2π/9), ±2sin(π/9)sin(2π/9)),
 * (2sin(4π/9)cos(2π/9), ±2sin(4π/9)sin(2π/9), 2sin(π/9)cos(4π/9), ±2sin(π/9)sin(4π/9)),
 * (2sin(4π/9)cos(2π/9), ±2sin(4π/9)sin(2π/9), –sin(π/9), ±sin(π/9)$\sqrt{1/[4sin^{2}(π/9)]+1/[4sin^{2}(4π/9)]}$),
 * (2sin(4π/9)cos(2π/9), ±2sin(4π/9)sin(2π/9), 2sin(π/9)cos(8π/9), ±2sin(π/9)sin(8π/9)),
 * (2sin(8π/9), ±2sin2(4π/9), 2sin(π/9), 0),
 * (2sin(8π/9), ±2sin2(4π/9), 2sin(π/9)cos(2π/9), ±2sin(π/9)sin(2π/9)),
 * (2sin(8π/9), ±2sin2(4π/9), 2sin(π/9)cos(4π/9), ±2sin(π/9)sin(4π/9)),
 * (2sin(8π/9), ±2sin2(4π/9), –sin(π/9), ±sin(π/9)$\sqrt{3}$),
 * (2sin(8π/9), ±2sin2(4π/9), 2sin(π/9)cos(8π/9), ±2sin(π/9)sin(8π/9)),
 * (–sin(4π/9), ±sin(4π/9)$\sqrt{3}$, 2sin(π/9), 0),
 * (–sin(4π/9), ±sin(4π/9)$\sqrt{3}$, 2sin(π/9)cos(2π/9), ±2sin(π/9)sin(2π/9)),
 * (–sin(4π/9), ±sin(4π/9)$\sqrt{3}$, 2sin(π/9)cos(4π/9), ±2sin(π/9)sin(4π/9)),
 * (–sin(4π/9), ±sin(4π/9)$\sqrt{3}$, –sin(π/9), ±sin(π/9)$\sqrt{3}$),
 * (–sin(4π/9), ±sin(4π/9)$\sqrt{3}$, 2sin(π/9)cos(8π/9), ±2sin(π/9)sin(8π/9)),
 * (2sin(4π/9)cos(8π/9), ±2sin(4π/9)sin(8π/9), 2sin(π/9), 0),
 * (2sin(4π/9)cos(8π/9), ±2sin(4π/9)sin(8π/9), 2sin(π/9)cos(2π/9), ±2sin(π/9)sin(2π/9)),
 * (2sin(4π/9)cos(8π/9), ±2sin(4π/9)sin(8π/9), 2sin(π/9)cos(4π/9), ±2sin(π/9)sin(4π/9)),
 * (2sin(4π/9)cos(8π/9), ±2sin(4π/9)sin(8π/9), –sin(π/9), ±sin(π/9)$\sqrt{3}$),
 * (2sin(4π/9)cos(8π/9), ±2sin(4π/9)sin(8π/9), 2sin(π/9)cos(8π/9), ±2sin(π/9)sin(8π/9)).