Triangular double truncatoprismantiprismoid

The triangular double truncatoprismantiprismoid is a convex isogonal polychoron and the second member of the truncatoprismantiprismoids that consists of 12 ditrigonal prisms, 12 ditrigonal trapezoprisms, 36 rectangular trapezoprisms of two kinds, 72 mirror-symmetric wedges and 36 rhombic disphenoids. However, it cannot be made uniform.

Using the ratio method, the lowest possible ratio between the longest and shortest edges is 1:a ≈ 1:1.84723, where a is the largest real root of 13x6+6x5+12x4-116x3-15x2+6x-14.

Vertex coordinates
The vertices of an optimized triangular double truncatoprismantiprismoid, using the ratio method, centered at the origin, are given by the Cartesian products of two ditrigons of DT1 and DT2:
 * DT 1 × DT 2 (where DT 2 is DT 1 scaled by b ≈ 1.78309, where b is the largest real root of 4x 6/ -16x 5/ +24x 4/ -16x 3/ +13x 2/ -12x-12),
 * DT 2 × DT 1.