> However I'm not sure how to do things in the first gif. Looks like you have to prepare a few different (but visually close) tiles for one "group" (say grass/d

> However I'm not sure how to do things in the first gif. Looks like you have to prepare a few different (but visually close) tiles for one "group" (say grass/dirt/sky/etc.) and when the designer drag the mouse the editor randomly chooses one tile from each group. Still I think it's a lot more complicated than I thought. The algorithm is called Wang Tiles. I think you identify a set of tiles which have edges compatible with each other by coloring them. Every time you place a tile, it will pick a random tile that meets all edge constraints. https://en.wikipedia.org/wiki/Wang_tile https://en.wikipedia.org/wiki/Wang_tile