Here is an example of a full-rank vertex of $\hom(\Box_3, \Diamond_4)$, where $\Box_3$ is the unit cube in the positive orthant and $\Diamond_4$ is the standard 4D cross polytope (ie., with vertices at $\pm e_i$); the vertex is expressed in two ways: v0*F11,v0*F15, v1*F4,v1*F7,v1*F9,v1*F11, v2*F4,v2...