What algorithm does the game use to check lines of spires? Specifically, would a line with gradient 3 be a valid line, if there was room to make one? Also, I need help with Spire X4 (see below the cut)
Actually, another thing. I think circle pylons should light up when activated.
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The solution to each of the Spire abyss levels has a "backbone" of two intersecting lines of gradient 2 or 1/2. However, I've experimented a bit in Spire 22, and it seems like only 4 of the possible backbones can be fleshed out into a solution. Am I doing something wrong, or is the solution to Spire X4 not formed this way? I don't want you to tell me the solution, just answer that one question.

