LACUNARY

Each body on the field is one slot from the current window. The bodies are not decorative and they are not seeded by a random number. Each one is constructed entirely from the hash of the slot it stands for, and everything it does follows from that.

The brain. Each body carries a small feedforward network: four inputs, four hidden units with a tanh activation, and two outputs. The inputs are the angle from the body's heading to the cursor, the inverse distance to the nearest other body, the current skip rate, and a slow drifting noise term unique to it. The outputs are a turn rate applied to the heading and a wave speed applied to the body. The weights are derived by hashing the slot hash and drawing all twenty four weights and six biases from a deterministic generator seeded by that value. A body's behaviour is therefore a fact about the block it stands for. It is identical for anyone reading the same window, and no part of it was chosen.

The wave. A body is twelve vertices arranged around a centre, and each vertex oscillates on a phase offset by its angular position, so a bulge travels continuously around the perimeter rather than the whole outline breathing in unison. The wave runs backward relative to the heading and the amplitude is weighted toward the trailing side, which is how a flatworm moves and why the motion reads as effort rather than as animation. Velocity is derived from wave speed and never set independently. When the wave slows the body slows, because the wave is the only thing moving it.

The stutter. A gap in the window is a block the network owed and did not deliver, and the field shows it as a hitch. When the sampled slots carry gaps, the wave breaks phase briefly and the body loses its footing before recovering. A clean interval runs smooth. A bad one runs ragged across the whole field at once, because every body is reading the same window and the gaps are not distributed between them.

What the body shows. Three properties, each reading one number from chain.

The still. When nothing has been settled for a long stretch, wave speed falls to a resting fraction across the whole field, the amplitude decays over a few seconds, and the bodies settle and drift. They do not vanish, they do not fade, and nothing is removed. A field that has stopped moving is a field that has stopped moving, which is a different thing from a field that is gone, and it is built to distinguish them. This is what a long quiet period looks like and it takes no explanation to read.

On the behaviour. Some bodies approach the cursor and some avoid it. Some are restless and some barely move. None of this was assigned, tuned or curated, and we could not have curated it without abandoning the property that makes it worth having. It is a consequence of the weights, and the weights are a consequence of the chain.