Physics Sandbox is a free 3D physics playground in your browser. Build contraptions and machines, edit maps, stack blocks and then let gravity do its thing. Powered by three.js and cannon-es with real rigid-body simulation. No install, no account — press play and start breaking things (politely). Best played on desktop with a mouse.
📜 The prompt (creator shared how it was made)
Create a single-file 3D physics sandbox with three.js and cannon-es: a map editor, placeable machines and blocks, and a play mode where everything simulates with real rigid-body physics.