If you're not aware, there's a relatively deep technical explanation of how sandspiel was built which I found interesting. If you're into orb.farm then you'll probably find it interesting, too: https://maxbittker.com/making-sandspiel
And, shameless plug, I've been teaching myself Rust/Bevy/ECS lately and am creating a simulation ant farm. The project is still in its infancy, and is nowhere near as cool as these, but https://meomix.github.io/symbiants/ for some ants that scurry around and emergently create piles of sand. Pan/Zoom launching in a couple of hours, feeding them hopefully in the next week or so. If you have ideas for simple features I'd love to hear them or if you want to follow along with the project check my profile for a Discord link.