Particle Sandbox

Prompt Claude Code Claude Opus 4.8 I want to add a doodle for a little particle sandbox game. The user can pick from a range of materials, and then they can paint those materials into the canvas. The canvas is a simulator playing forward in time, and the materials immediately begin being simulated as they're painted. The different kinds of particles interact with each other. Particles/materials might include wood, metal, sand, wind/fan, lava, stone, wall, gunpowder, and any other materials that might be fun in a sandbox environment like this. Particle interactions might include wood catching fire, lava and water combining to turn into stone, gunpowder encountering fire and exploding destroying nearby materials, wind/fan kicking-up sand in the air, etc. There should be a wide range of materials and interactions, so be creative!

I want to add a doodle for a little particle sandbox game. The user can pick from a range of materials, and then they can paint those materials into the canvas. The canvas is a simulator playing forward in time, and the materials immediately begin being simulated as they're painted. The different kinds of particles interact with each other. Particles/materials might include wood, metal, sand, wind/fan, lava, stone, wall, gunpowder, and any other materials that might be fun in a sandbox environment like this. Particle interactions might include wood catching fire, lava and water combining to turn into stone, gunpowder encountering fire and exploding destroying nearby materials, wind/fan kicking-up sand in the air, etc. There should be a wide range of materials and interactions, so be creative!

Pick a material, then click and drag to paint it straight into a world that's always simulating. Everything obeys a little cellular-automaton physics: powders pile, liquids find their level (and layer by density, so oil floats on water), gases rise and fade.

The fun is in the interactions:

Fire spreads to anything flammable (wood, oil, plant, coal, seeds) and is doused by water (with a puff of steam).
Lava sets fire to its neighbours, melts metal, fuses sand into glass, and (the classic) hardens into stone the instant it touches water, which flashes to steam.
Gunpowder detonates on contact with any flame or lava, carving a crater and chaining into nearby powder.
Acid eats through most things (but not glass or walls, so build a container).
Water → steam → water: boiled water rises, cools, and rains back down.
Fans blow an updraft that kicks powders and lights into the air; drop a fan under a dune for a sand fountain.
Seeds sprout into plants near water; plants creep along anything wet; salt dissolves in water and melts ice.
Cloner learns the first material that touches it and emits an endless supply.

Tips: scroll on the canvas to resize the brush, space to pause, right-drag (or the Eraser) to remove. The world starts with a small diorama, so try setting the trees alight, or dropping lava into the pond.