Optimising layout of items in a grid

Hi, all,

I figure this should probably be done in VBA, though I could be wrong.

I've got a grid of variable size - let's say 9*9 for argument's sake. In this grid, I want to lay out two values - let's say A and B - with the constraint that every A must be horizontally or vertically adjacent to a B. Diagonal matches don't count.

How can I maximise the number of A's in the grid?

This is a heuristic/brute force-type approach:

checks.xlsm

DoEvents is in in case you need to Ctrl-C out of an endless loop (but won't happen for the 4x4 grid)

I'm not sure it's a viable solution for a 9 x 9 grid though, I haven't tried.

If you need maximum crunching ability, you could implement this as pure-vba quite easily.