Some ideas I saw on the intertubes, Ron.
1) Flank includes opposite sides (normal) plus the corner spaces on either side.
2) After a target is flanked, all those who border the target get flank on that target.
3) The bonus for flank = the number of flankers.
The idea is to make flanking more tactical (and probably more realistic), and to make being swarmed a lot more dangerous. If an entire litter of puppies attacks you, you’re going to get licked good.