A sea-squirt tadpole steered by the published wiring of a real larval brain, every neuron stepping every tick.
Brain wiring: Ryan, Lu & Meinertzhagen (2016), eLife 5:e16962, CC BY 4.0. The larva runs the contract's integer engine in your browser; nothing is written on-chain.
The larva turns toward your light while its photoreceptors fire, and swims in bouts. That turn is a game rule: the published wiring does not carry a bearing, and the animal's reflex points the other way. Pass the seven light gates, reach the settlement shelf, and claim a free reef cell once the larva has 1,200 ticks, before rival larvae take the cells. Pause and pick a race track to lock the lamp to one of the chain's courses.
The larva runs the reconciled 224-cell connectome in research/connectome.v1.json, built from Ryan et al. 2016: 3,010 chemical connections, 428 gap junctions and 28 inhibitory cells. Every tick is stepLarva from client/src/engine.js, the integer mirror of contracts/brain/sources/brain.move that the larva verifier also uses. The genome sets each cell group's threshold and leak, the sensory gains and a left/right motor bias. The body integrator turns spikes into heading, tilt, thrust, escape swims and yolk burn.
Each tick takes what a swim_tick transaction carries: the light's position as unsigned integers, its level (0 to 256), a shadow flag and a pulse flag. PR-I photoreceptors read the light, shaded by where the ocellus faces, and turn the larva toward it while they fire. That turn is a game rule. A passing shadow drives the PR-II cells, and enough of those spikes start an escape swim through the body's counter, not through the motor neurons. Depth changes only while the light is dimmed, from the tilt the antenna cells already set. Spike adaptation stays after a swim. It is not memory, and it does not make the next swim quieter.
Simulated here: the genome (drawn in the browser in place of sui::random), the reef cells, rivals, gates and the shadow's path. The 20-minute competence clock is skipped, and nothing is written to a chain. Ticks run at 20 per second; on-chain each tick is one transaction. The larva's depth, roll and tail beat are drawn over the integer pose, at 80 engine units to the millimetre. The pulse flag only costs yolk in brain.move, so the demo never sets it.
Wiring data: Ryan K, Lu Z, Meinertzhagen IA (2016) eLife 5:e16962, CC BY 4.0. Sign assignments after Kourakis et al. 2019 and Bostwick et al. 2020.
Demo record, not on-chain. The state hash, ticks, spikes and pose are what brain.move would hold after this run's inputs. Save the run and open it in the larva verifier to replay every tick. On Sui this becomes a frozen LarvalRecord object and the adult keeps its reef cell (DESIGN §6).
Larvae don't feed. This one used its last yolk before it reached a free reef cell. Its genome stays readable in the Tunic Bed.