Idea: (bn)(b(n-1)) will have the same triangles as (an)(a(n-1)) but with a different square.

When VQC took us through nn+2d(n-1)+f-1 and made a coloured diagram, he said "the colours in the MAP will be the KEY to GUIDE you through the process of how the algorithm works." As I was going through RSA #10 for the Grid Patterns thread the other day I noticed this post and that nobody had said anything about it. Well, consider this. This first picture is the one he posted at the time. It has several specific colours. Picture 2 (confusingly named "colours 1.png") is another picture he posted a couple months later in RSA #12. It has very similar colours. The colours are most likely linked, I think.