Two-orbit polytope

A two-orbit polytope is a polytope with exactly two types of flags. All Coexter-def quasiregulars are either regulars or two-orbits, and the regular ones can be made into two-orbits by two-coloring the faces in a certain way, like for example the octahedron can be two-colored to make the tetratetrahedron, a two-orbit. Not all of the regulars can be turned into two-orbits like this, and some (the hypercubes) require vertices to be two-colored instead. All 2D semiunifoms are two-orbits, and so are their duals.