This is a small tool I've developed to experiment with the reaction-diffusion. Is's pretty slow (~10 ms for 1 simulation tick on my cpu). I plan to rewrite into shader.
If you'd like to know more about this simulation check this.
If you're looking for a tool to experiment yourself go toake a look at: this.
My simulation results:
Simulations with feed and kill changing linearly.
Evolution of the 'corals' pattern:
