Falling Sand is a pixel physics sandbox you can play right here — no download, no sign-up.
Every pixel on the canvas is a tiny grain of something. Sand piles up into dunes, water finds its level, oil floats on top of water, and lava creeps slowly downhill, setting fire to everything it touches. Pick an element, draw on the canvas, and hold still to keep pouring.
Nineteen elements
Sand, water, wall, wood, fire, oil, lava, plant, ice, snow, acid, gunpowder, stone, glass, steam, clone, salt, seeds and an eraser. Each one has its own weight and behavior: powders fall and slide, liquids spread sideways, gases rise and fade, and fire flickers upward until it burns out. Some materials only appear when others react — mud, brick, ash, salt water and flowers.
Twenty-two reactions to discover
Elements react when they touch. Lava quenched by water turns to stone. Lava on sand makes glass. Sand left in water turns to mud, and fire bakes mud into brick. Salt dissolves into salt water, which sinks below fresh water and never freezes; boil it dry and the salt is left behind. Sprinkle salt on ice and it melts, the way road salt keeps winter streets clear. Burnt wood leaves ash, and seeds planted next to ash grow taller and bloom into bigger flowers. The reactions panel shows a hint for each one you have not found yet — see if you can light up all twenty-two.
Grow a flower garden
Drop seeds on sand, mud or ash and give them a drink. Each one sprouts, pushes a green stem upward and opens into a flower in pink, purple, red or white. Water a whole row and watch a meadow come up.
Ready-made scenes
Start from an erupting volcano, a sand hourglass you can flip over and over, a rain garden fed by two clone taps, a frozen lake with a cabin on the shore, or a flower field waiting for its water tank to open — or clear the board and build your own. The Flip button turns the whole sandbox upside down, so anything you build can run again. The purple clone block copies the first element it touches and keeps producing it forever, which is the secret to fountains, waterfalls and endless lava flows.
Saved automatically
Your sandbox and the reactions you have found are saved in this browser. Sign in and they follow you to any device.