In trying to find a relationship between (x+n) and c, I ran into gradients again. I don't know if anyone remembers what happened last time (4 or 5 months ago) but this probably isn't going to lead anywhere useful.

Since we all seem to be coming towards this from completely different angles, I'll explain my current thinking. If you look at the last pictures in my post >>5581 here, you can visually see where the cutoff is from the infinite set of values for which (x+n)^2 = f to the finite set we actually need to figure out the math for. I have a feeling we'll find the answer in some way that will be analogous to figuring out a mathematical ruleset that would be used to construct the finite set from a given c value. So obviously it's far more likely that we'll figure it out with pictures and symmetry, but thinking of it in the context of series math might show us more relationships. I mean, you can see that all the n, d, x, a and b values follow incremental patterns. It's just e and f are all over the place.