These procedurally generated blocks support Hilbert Curve grooves which are scaled. In the above screen shot I'm using a scale of three, which means there are two voxels between each voxel groove. To calculate the the ideal "order" for the Hilbert Curve function based on the bounds of the block (or world selection bounds) I use the following math/code: 

int order = log2i(clampMin(pow2Ceil(divCeil(max(bounds.width(), bounds.height(), bounds.depth()), scale)), 2))

FYI, all of these nested function calls are of functions in my C++ (template) math library.

And the inverse Hilbert Curve function I wrote is based on code from here:
https://people.math.sc.edu/burkardt/cpp_src/hilbert_curve/hilbert_curve.html