Digonal duocomb

The digonal duocomb is a degenerate regular polyhedron consisting of 4 squares. It can be formed as the comb product of two digons, meaning it has the extended Schläfli symbol $$\{4,4 \mid 2\}$$. It is self-dual, self-Petrie, and there exist points that are connected by 2 different edges (like the digon). It can be obtained by halving the halved square duocomb.

Despite the digonal duocomb containing square faces, its halving is not a valid abstract polytope due to the diamond condition.

It is the smallest possible abstract regular polytope with the Schläfli type.