Boxes fall, tumble and pile up against static walls. nacatamalon/physics2d is an opt-in adapter: a game that never imports it never pays for Rapier's WASM. Rapier steps at a fixed rate and writes each body back onto its object, in pixels and with y pointing down.
Click the canvas to kick the pile. Impulse is mass times speed, and mass is density times area in pixels: that is why the numbers are so large.