This demo by Lutz Rosema is a fun cellular autonoma (Game of Life) style simulation featuring three different types of “cell”: wolves, sheep, and grass. The demo is based on an old BASIC program (which makes it that much cooler in my book). Try tweaking the variables to modify the probability of each event.
I’m absolutely fascinated with cellular autonoma simulations like Conway’s Game of Life, which makes Terra pretty amazing. It’s a library that simplifies building these sorts of simulations.