Enneagonal antiditetragoltriate

The enneagonal antiditetragoltriate or eadet is a convex isogonal polychoron and the seventh member of the antiditetragoltriate family. It consists of 18 enneagonal prisms, 162 rectangular pyramids, and 162 tetragonal disphenoids of two kinds. 2 enneagonal prisms, 4 tetragonal disphenoids, and 5 rectanguar pyramids join at each vertex. However, it cannot be made scaliform.

It can be formed as the convex hull of 2 oppositely oriented semi-uniform enneagonal duoprisms where the larger enneagon is more than $$\frac{1}{\cos\frac\pi9}$$ times the edge length of the smaller one.