The Bounce Panel

Boids is three rules pretending to be a society. Bounce is the opposite number: no rules of behavior at all. The toy's own description says it in seven words — “Nothing steers. Everything collides. Momentum in, spin out.” Every body flies dead straight until something gets in the way; everything interesting happens at the moment of contact.

A collision trades momentum along the line of contact — hit something off-centre and part of the push becomes spin, which is why the sticks cartwheel. Bounciness 1 conserves energy forever; below 1 every impact bleeds a little away (in zero gravity a gentle stir keeps the tank from going still).

Provenance, locally. Unlike its glasswall siblings, this toy owes nothing to WLED and almost nothing to anyone. Its only ancestor is Eric's early work on Pongo — a project that lived a brief life in Figma and left behind principles that will arise again. In this lab, bounce arrived mostly in a single prompt; mass and friction were added shortly after.