A playable observatory for tiny universes
Every future leaves a trace.
It's not a simulator. It's an observatory with a time machine.
First, the basics
Take a grid of square cells. Each one is either alive or dead. Pick a starting pattern — that's the only decision you ever make. Then the grid updates, all at once, forever, under three rules:
That's it. There is no player once it starts, no score, no opponent — you set a beginning and watch what the rule does with it. And what it does is the surprise: from these three trivial rules come still lifes that never change, oscillators that blink in place, gliders that walk diagonally across the grid forever, and guns that fire an endless stream of them. The rule is even Turing-complete — you can, in principle, build a working computer out of nothing but this grid. Smart, simple rule; genuinely astonishing results. That gap is the entire appeal of Conway's Game of Life, and it's sixty years old.
A glider: five cells, repeating its own shape every 4 generations, one cell further down-right each time. This is a real simulation, not a loop of frames.
Then, the difference
Underneath, AFTERLIFE runs the exact same rule everyone above just read — B3/S23, standard Game of Life, no variant. Plenty of Life simulators exist already and most stop there: draw, press play, watch it run. AFTERLIFE asks a different question of the same rule — not can it run fast, but what happens if you touch one cell? That means treating time itself as something you can hold, not just a direction the simulation happens to go.
A ribbon along the bottom holds the world's entire recorded history — scrub it backward and forward like an editing timeline, not a progress bar. Lift a stretch of it out and it becomes a 3D Time Sculpture: the third axis is time itself, so a still life becomes a vertical column and a travelling glider becomes an inclined beam. You orbit it, slice it, and read a whole encounter from the side instead of replaying it.
Change a cell at some earlier generation and the obvious thing would be to overwrite everything that happened after it. AFTERLIFE does the honest alternative instead: it forks. Your original future keeps running on its own branch; your edited future runs on a new one. A difference lens then shows exactly which cells diverge between the two, generation for generation — both outcomes stay yours, side by side.
As recognisable shapes appear on the grid — a still life settling out of debris, an oscillator ticking in place, a glider breaking free — a recognition pass names them and logs the discovery, buildling a personal field guide of what's actually happened in your universe, plus three small authored experiments built on the same mechanics.
The best explanation of AFTERLIFE is watching it for thirty seconds. Something is always alive somewhere on the grid.