Interesting idea.
One question:
what happens if it is surround by 3 pairs of creatures each one different:
e.g. 2 green dragons, 2 toads, 2 cockatrice
something like this:
gr.dg. gr.dg.
gn.td. chm gn.td
cktr cktr
6 creatures total, 3 pairs.
Or does it only count left and right?