Game of Life — live coded

Inspired by Bret Victor's Inventing on Principle (2012) · see also worrydream.com.

Conway's Life with every rule in the editor. Edit the BIRTH / SURVIVE sets to invent new automata (Conway = B3/S23, HighLife = B36/S23, Day&Night = B3678/S34678, Seeds = B2/S). Toggle WRAP? for a torus, swap NEIGHBORHOOD between Moore and von Neumann, or rewrite cell-color for a fresh palette. State is preserved across every edit — click cells to toggle them while it runs.

Click toggle a cell · Drag paint cells alive · hold Alt/Ctrl + drag any number in the source for a live scrubber

How it works

• The grid lives in a Uint8Array on the JS side, so re-evaluating the source never touches it. JS owns state, cljrs owns rules.
• Every frame, JS sends a flat [w h wrap? n0 n1 ...] packet to (next-grid ...) via repl.call_ints; cljrs returns the next generation as a flat vector. One Clojure call per frame, no per-cell crossings.
• BIRTH / SURVIVE are sets — change them and the next frame uses the new rule. The grid keeps evolving.
• cell-color is a pure function of (alive? neighbors age) returning a packed 0xRRGGBB int. JS pulls the palette via call_ints too.