I used to play a lot of the powder toy when I got my first computer, and I always wanted to make such game myself. And so you can play it here!   https://pitergroot.itch.io/falling-sand-engine 

This is more like a demo / prototype since it's still in development. But I already really like to just play around with the different elements. 

For those that dont't know, a falling-sand-game is a game where you can place different particles / elements on a 2D plane wich all have unique interactions with each other.