Octagonal-enneagrammic duoprism

The octagonal-enneagrammic duoprism, also known as ostedip or the 8/9-2 duoprism, is a uniform duoprism that consists of 9 octagonal prisms and 8 enneagrammic prisms, with 2 of each meeting at each vertex.

The name can also refer to the octagonal-great enneagrammic duoprism.

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


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