Enneagonal duotransitionalterprism

The enneagonal duotransitionalterprism is a convex isogonal polychoron and the eighth member of the duotransitionalterprism family. It consists of 18 enneagonal trapezorhombihedra, 18 enneagonal prisms, and 81 rectangular trapezoprisms. 2 enneagonal trapezorhombihedra, 1 enneagonal prism, and 2 rectangular trapezoprisms join at each vertex. It can be obtained as the convex hull of two orthogonal enneagonal-octadecagonal duoprisms. However, it cannot be made scaliform.

Using the ratio method, the lowest possible ratio between the longest and shortest edges is 1:$$1+\sqrt2\cos\frac{\pi}{7}$$ ≈ 1:2.32893.