As a fan of both Neal and R74n this was an unexpected collaboration!

I can highly recommend building your own falling sand simulator. It's really fun to see how such simple rules create emergent behaviors. Sand pixels try to move down, then diagonally down. Water does the same, then tries sideways.

Me messing around with it eventually resulted in a game I'm now working on full time (think Noita meets Factorio): https://store.steampowered.com/app/2764460/Sandustry/