Digonal-triangular duoantiprism

The digonal-triangular duoantiprism or ditdap, also known as the 2-3 duoantiprism, is a convex isogonal polychoron that consists of 4 triangular antiprisms, 6 tetragonal disphenoids, and 12 digonal disphenoids. 2 triangular antiprisms, 2 tetragonal disphenoids, and 4 digonal disphenoids join at each vertex. It can be obtained through the process of alternating the square-hexagonal duoprism. However, it cannot be made uniform, as it generally has 3 edge sizes, which can be minimzed to no fewer than 2 different edge lengths.

Using the ratio method, the lowest possible ratio between the longest and shortest edges is 1:$$\frac{\sqrt{30}}{5}$$ ≈ 1:1.09545. In this specific variant the tetragonal disphenoids become fully regular tetrahedra. A variant where the triangular antiprisms become fully regular octahedra also exists.

Vertex coordinates
The vertices of a digonal-triangular duoantiprism, assuming that the triangular antiprisms are regular octahedra of edge length 1, centered at the origin, are given by: with all even changes of sign, and with all odd changes of sign except for the first coordinate.
 * $$\left(0,\,\frac{\sqrt3}{3},\,\frac{\sqrt6}{6},\,\frac{\sqrt6}{6}\right),$$
 * $$\left(±\frac122,\,\frac{\sqrt3}{6},\,\frac{\sqrt6}{6},\,\frac{\sqrt6}{6}\right),$$

An alternate set of coordinates where the tetragonal disphenoids become regular tetrahedra of edge length 1, centered at the origin, are given by: with all even changes of sign, and with all odd changes of sign except for the first coordinate.
 * $$\left(0,\,\frac{\sqrt3}{3},\,\frac{\sqrt23}{4},\,\frac{\sqrt2}{4}\right),$$
 * $$\left(±\frac12,\,\frac{\sqrt3}{6},\,\frac{\sqrt2}{4},\,\frac{\sqrt2}{4}\right).$$