one easy way to make a simulation of falling sand piling up- just define what happens for all 16 possible 2x2 grids, and repeatedly apply these rules to the picture

this is a 2d cellular automaton, and I made the animation with @WolframResearch Mathematica

this is an improvement on a previous post I took down- thanks @paulgb for the idea to include rules that make the sand spread and take advantage of the full 2x2 pattern size

There is an amazing environment by @Todepond on it: which was inspired by @maxbittker’s Sandspiel:

i rejoice in the “just put lotta if-else statements” vibe of this tweet

the 2x2 groups overlap.. how are they actually evaluated?

kinda like what shaders do. break down the scene to a set of rules per-pixel and then applying those rules in parallel

The number of yellow squares (grains of sand) is not conserved. A grain stacked on top of another grain will fall to both sides if available. this three column setup: _+_ _+_ turns into: _ _ _ +++ and the grain on top gets doubled to either side of the grain on bottom.

Depends how you implement applying the rules

Pretty neat! Leads to some impossibly tall columns, wonder what an easy way would be to introduce settling/cascades... maybe randomized horizontal swaps ("it was the wind!1!")?

There is a rule that makes tall columns crumble