Game of Life Text Generator

The premise

A Life board takes no input after generation zero. Everything it will ever do is already sitting in the starting cells, which makes the useful question a backwards one: given a picture, what start produces it?

This program answers that for text. The board above is its output — 318 gliders that spend 436 generations flying at each other and stop as the words GAME OF LIFE. The one at the top of the front page is the same program run on my name, settling at generation 276.

How it works

The renderer turns each glyph pixel into a 2×2 block, a still life, so once it exists it stays put. That leaves the planner 159 blocks to build out of gliders without any of the deliveries running into each other.

It works outward from the centre of the text. Each block gets two gliders aimed to collide on it, launched from the pair of outward directions its position implies and delayed by whole glider periods until the flight path is clear of everything already placed. The delay is the trick. A block whose gliders would cross an earlier delivery waits its turn, and there are 256 slots to try before the planner gives up on it.

What it never does is run the combined board to find out whether a slot works. It proves that instead: no live cell of the candidate ever comes within a move of a live cell of a placed block at the same generation, and every dead cell taking neighbours from both flips the way it would flip for each of them alone. Both are checked against a running record of where every placed block has been, generation by generation. The finished construction is simulated once at the end, and refused if the last cells are not exactly the text that was asked for.

Two front ends

The desktop app is PySide6. The browser version at conway.martinsundal.no runs the same Python planner in a Pyodide worker, with the canvas and simulation loop in TypeScript. First visit downloads the WebAssembly runtime and NumPy, then caches them.

Patterns export as RLE, so anything it builds opens in Golly or LifeViewer like any other Life pattern.