Heptagrammic-octagrammic duoprism

The heptagrammic-octagrammic duoprism, also known as shestodip or the 7/2-8/3 duoprism, is a uniform duoprism that consists of 8 heptagrammic prisms and 7 octagrammic prisms, with 2 of each meeting at each vertex.

The name can also refer to the great heptagrammic-octagrammic duoprism.

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


 * (1, 0, ±sin(2π/7)($\sqrt{2–√2}$–1), ±sin(2π/7)),
 * (1, 0, ±sin(2π/7), ±sin(2π/7)($\sqrt{2}$–1)),
 * (cos(2π/7), ±sin(2π/7), ±sin(2π/7)($\sqrt{1/[4sin^{2}(2π/7)]+(2–√2)/2}$–1), ±sin(2π/7)),
 * (cos(2π/7), ±sin(2π/7), ±sin(2π/7), ±sin(2π/7)($\sqrt{2}$–1)),
 * (cos(4π/7), ±sin(4π/7), ±sin(2π/7)($\sqrt{2}$–1), ±sin(2π/7)),
 * (cos(4π/7), ±sin(4π/7), ±sin(2π/7), ±sin(2π/7)($\sqrt{2}$–1)),
 * (cos(6π/7), ±sin(6π/7), ±sin(2π/7)($\sqrt{2}$–1), ±sin(2π/7)),
 * (cos(6π/7), ±sin(6π/7), ±sin(2π/7), ±sin(2π/7)($\sqrt{2}$–1)).