Watch it generate. Hold space to erase tiles. (This will temporarily pause generation until space is released) I like cutting islands in half and watching the islands try to re-assemble
I got the idea from how wave function collapse works. It's not exactly wave function collapse but its a bit similar. Pretty much, at the start forest tiles are randomly placed on the map. Then it uses these rules: Forest tiles can only generate grass, forest and nothing. Grass tiles can only generate sand. Sand can only generate sand. Water can only generate water.
