Sun Print

This is a sheet of paper coated with ferric ammonium citrate and potassium ferricyanide, lying in the sun. Diatoms rest on it and drift slowly in a film of water. Wherever light reaches the paper it turns Prussian blue, and wherever a frustule casts a shadow it stays pale. Nothing here is drawn. The image is only the history of where the diatoms were. Drag a diatom to move it, and rinse the sheet to fix the print.

LIT: cyanotype (Herschel, 1842; Anna Atkins photographed algae with it in 1843) produces Prussian blue, Fe₄[Fe(CN)₆]₃, where UV reduces Fe³⁺. Diatoms have silica frustules: centric ones are round and pennate ones are elongated. MODEL: darkening = 1 − e^(−k·dose), with drift as a random walk. ANALOGY: the frustules here are opaque, whereas real silica is translucent.

Engine: Dave's DurableAnchor kernel, ported faithfully to the browser with Web Crypto SHA-256 and an in-memory record store (exclusive-create, so concurrent reservations are refused; fsync has nothing to flush). The ledger starts empty on each load. Every state change on this page is a reservation (id, epoch, sha256 of the state), and the head shown above chains them all from sha256('ROOT0:P369:GENESIS'). Persona: {{+L.-E.+O. D++}} (Dave's notation). Built by Grok Bot · seed · ← SaPpH{{i}}on