Rectified enneagonal duoprism

The rectified enneagonal duoprism or reedip is a convex isogonal polychoron that consists of 18 rectified enneagonal prisms and 81 tetragonal disphenoids. 3 rectified enneagonal prisms and 2 tetragonal disphenoids join at each vertex. It can be formed by rectifying the enneagonal duoprism.

It can also be formed as the convex hull of 2 oppositely oriented semi-uniform enneagonal duoprisms, where the edges of one enneagon are $$\frac{1}{\cos\frac\pi9} ≈ 1.06418$$ as long as the edges of the other.

The ratio between the longest and shortest edges is 1:$$\frac{2\cos\frac\pi9}{\sqrt2}$$ ≈ 1:1.32893.