Sandboxels is available to play in the browser: https://sandboxels.r74n.com/

Or, get it on Steam: https://store.steampowered.com/app/3664820/Sandboxels/

Sandboxels is a falling-sand simulator featuring heat simulation, electricity, density, chemical reactions, cooking, and fire spread. With over 500 unique elements to play with, Sandboxels is a great way to pass the time and relax.

Developed by R74n: https://r74n.com/

As seen on TikTok and YouTube.