Really cool tool. One detail: the instructions do not say what selecting tiles or lines do, it doesn't seem to do anything besides highlight the item on the other panel, what is that for?
Looks like they illustrate the dual nature of how line intersections in the grid map to equilateral polygons in the tiles. It wasn't obvious to me until I read the "how it works" section.
https://github.com/aatishb/patterncollider#how-it-works