I guess I could say that two spaces are diagonally adjacent if they share nothing but a corner, and there is a straight path from approximately the center of one space to approximately the center of the other that passes only through that corner without passing through other spaces. For A4 and b4, the only straight path between their centers would go through a4
I guess I could say that two spaces are diagonally adjacent if they share nothing but a corner, and there is a straight path from approximately the center of one space to approximately the center of the other that passes only through that corner without passing through other spaces. For A4 and b4, the only straight path between their centers would go through a4