A crash test for the versatile ClipperJS geometric library. A grid made by 128x128 square cells is populated, creating a square with a probability of 90% or a hole in the remaining 10%. The squares are then merged to create a single region, that is finally displayed in a zoomable SVG.
The heaviest operation turns out to be the merging (surprise!), taking the vast majority of the execution time (you can open a JavaScript console to see when each operation begins).