Aligning one polyhedron with another is a two stage process. The
polyhedron to be aligned is aligned with a standard symmetry using
the -y option. The standard symmetry is then aligned with a subgroup
of the same type in the fixed polyhedron using the -Y option.
In this case, a C3v subgroup of a hexagonal pyramid is aligned with
a C3v subgroup of a cube.
View this model with the command
polygon pyr 6 | off_trans -y C3v -Y cube,C3v | antiview - cube