  A real-space method using generating integers is used to classify the
possible moire patterns for two equal hexagonal lattices. The result is that
the rotations that take (n,m) to (m,n) with n,m relatively prime form the
fundamental moire transformations, and the number of lattice coincidence areas
within each supercell is given by (n-m)^2. The scheme may be extended to cases
where the lattice constants differ. Additionally, we consider a system with a
transition metal between the layers of a twisted bilayer of h-BN. We find that
the lowest energy configurations for such an arrangement are those at aligned
and anti-aligned sites of the moire pattern, depending on the transition metal,
and the low-symmetry sites possess high magnetization.
