SHIBORI The artist chooses the fold.

In shibori — Japanese shaped-resist dyeing — cloth is folded, bound and dipped. The maker controls the binding with great precision. What the dye does inside that constraint is not controlled at all: it is settled by capillary action, by how hard the thread was pulled, by how long the bolt sat in the vat.

Gray‑Scott reaction‑diffusion is the same division written in chemistry. Two substances, one feeding on the other, governed by a feed rate and a kill rate. From that: coral, labyrinths, dividing cells. Nothing in the equations knows what a coral is.

So each work is built the way the cloth is. A binding decides where. A reaction decides what.

This is not shibori. It is a simulation of the geometry of resist. The vocabulary is borrowed, with attribution, from Arimatsu‑Narumi (Aichi, designated a traditional craft in 1975) and Kyō‑kanoko (Kyoto). Neither tradition is associated with, nor endorses, this project.

Each shown alone, then composited. This is the real draw order, rendered from the shader itself with one early return per pass — not a diagram drawn afterwards.

The cycle closes exactly, and it is tested rather than asserted. tools/loop.mjs renders the last instant of a turn and the first instant of the next, seventeen milliseconds apart, and measures that step against the same interval sampled at five points mid‑cycle. A term that fails to return measures about 12× its controls. The shipped build measures 0.99×.

Two of these figures are arguments rather than dials. Kanoko (Fawn Spot) is the rarest technique at 10% because hon‑hitta — the finest grade — runs to roughly 150,000 hand‑tied knots per bolt. Tomekon (Stopping Navy) is not a different dye at all: it is indigo worked to the end of its range, so it is reachable only at twenty dips, and a three‑dip Tomekon cannot be minted.

Math.random appears nowhere in the artwork. Every value — traits, geometry, palette, composition — is drawn from one seeded generator, so a hash and a render are the same object seen twice.