Cellular noise
Example Links
https://github.com/ashima/webgl-noise/blob/master/src/cellular2D.glsl
Modulo 7 without a division
Permutation polynomial: (34x^2 + 6x) mod 289
Cellular noise, returning F1 and F2 in a vec2.
Standard 3x3 search window for good F1 and F2 values
Sort out the two smallest distances (F1, F2)