Chris Cox sent me his offset grid code[1] that produces irregular looking rectangle grids[2] where each rectangle in the output corresponds to exactly one grid space. I admit I didn't think this was possible. I had been thinking that if I move the vertices around, they won't be rectangles anymore, and if I move the edges around, they won't line up anymore. His solution is clever and simple!
I wanted to try recreating it. Click animate to see how a square grid turns into the rectangle grid.
Coloring
Source: offgrid-visualization.js
The Sylves library supports offgrid[3].