Open any brain
Real spikes along real synapses, the reward signal it learns from, and the synapses a life has rewritten — gold where they grew, violet where they faded.
The one rule
Nothing in this world is scripted
There is no findFood(), no behaviour tree and no state machine. Innate reflexes exist only as ordinary synapses that a lifetime of learning is free to rewrite. What you watch is what the brains, the bodies and the ecology produce — and you can open any brain and see the spikes that just fired.
341+24spiking neurons per person — and room to grow 24 more as they live
71behaviours in the atlas — none of them written
42laws to write into a world’s charter
153codex entries, 30 challenges, a daily world
v3 · the Evolution update
Seven rules. Everything else grows.
What used to be written content is now generated while the world runs. Skills, instincts, faces, peoples, the style of their houses and the ages the world passes through come out of seven base rules — and there is no last one of any of them.
- Land. The island is a grid: every standing thing owns its cells, nothing overlaps, people walk freely.
- Body. Senses, a spiking brain, muscles. The world answers only the muscles.
- Growth. At a moment that matters a brain grows a neuron — a skill nobody wrote — and prunes the ones that stop earning their keep.
- Heredity. The skills that served a parent best are born into the child as instincts.
- Drift. Looks drift freely; a group that settles apart becomes a people with its own name, colours and roofs.
- Time. Every year a new age, drawn from the seed: plenty, frost, hunters, change — each with an omen.
- Fate. Crises by chance, harder as the settlement grows.
What you do
Write the laws. Watch. Understand.
You are an observer with a budget, not a ruler. Favour grows when the world thrives; you spend it on rain, food, a blessing — or a pulse of reward into one brain.
Seasons and eras
An eight-day year: spring growth, summer thirst, autumn harvest, winter snow. Hearth, camp, village, town, city — read from the world, never unlocked by a button.
Fate, with a day’s warning
Drought, harsh winter, predator migration, blight, flood, fever, wildfire, eclipse. Crises change the physics of the world; how a village copes is up to its brains — and to what you do with the warning.
An atlas of the unwritten
An observational classifier names what it sees — the Provider, the Night Watch, the Irrigator, the Mourner — with a stated criterion you can check. Epithets follow people into the chronicle and their obituaries.
Found on the way
The brains were erasing their own reflexes
Thirsty people stood at the shore and did not drink. The measurement: the innate thirst → drink synapse fell from 1.80 to 0.05 in ten simulated minutes, in every brain — and turning its plasticity off did not stop it.
The cause was homeostatic synaptic scaling: it held each neuron’s total input constant, so as learning grew a motor neuron’s other inputs, the reflex was scaled away with them. Scaling now leaves the reflex arcs alone; over thirty thousand ticks they hold at 1.78.
“Measure the derived quantity.” Every fix in this project started with a probe that measured what the brain was actually doing — the thirst probe, the drink-weight probe, the steering probe — and the failures stay in the implementation log.
Measured, not claimed
Eight worlds, 200 000 ticks each
Same seeds, shipped defaults, two predators, no interventions. The simulation is deterministic, so anyone can rerun these numbers with npm run balance:parallel.
| World | Outcome | People | Generations | Era | Crises |
|---|---|---|---|---|---|
| eden | thriving | 152 | 5 | III · Village | drought |
| lumen | thriving | 117 | 5 | III · Village | drought, flood |
| tessera | thriving | 33 | 5 | III · Village | two droughts |
| vela | thriving | 23 | 4 | II · Camp | drought |
| auriga | runaway | 251 | 5 | III · Village | drought, predators |
| solace | declining | 3 | 3 | II · Camp | two droughts |
| orion | extinct | 0 | 2 | II · Camp | harsh winter |
| kepler | extinct | 0 | 2 | I · Hearth | — |
Still open: thirst is the leading cause of death (steering saturates when need is high), and nothing yet caps a thriving world below the hard limit.
Videos
See it before you play it
How it is built
A pure, deterministic core
Simulation
- Strict TypeScript, no ML library
- Leaky integrate-and-fire network, reward-modulated Hebbian learning from the body’s own physiology
- Same seed + same commands = byte-identical history; a replay is a few hundred bytes
Observatory
- React + PixiJS diorama, the world in a Web Worker
- Canvas brain view with real spikes and a porthole into the world
- Saves packed as exact float32, gzip in IndexedDB
Evidence
- 202 unit and integration tests
- Headless acceptance and multi-seed balance harnesses
- Probes for every claim, in
scripts/