Symmetry and rules
It seems I’ve decided a good basic rule for the genetic algorithm to work with: it should attempt to create a tiling pattern where the edges connect. Thus the pattern while running, will do something like this simplified version, which would eventually reach a checkerboard pattern:
Another selection criteria would be the symmetry of the pattern inside the tiles, which might lead to interesting results the patterns would become more regular. I also managed to create a simple grid of equilateral triangles which might or mightn’t be useful.