Ink Marble

Ink Marble recreates the paper-marbling technique where ink is floated on water and combed into patterns before being lifted onto a sheet. Tapping the surface drops a disc of ink, and every drop already floating gets pushed outward to make room for it. That displacement is the entire craft: ink never covers what came before, it wraps around it. Drop into the middle of an existing pool and you get a perfect ring; drop off to one side and the whole pattern slides and stretches away from your finger.

The displacement uses the actual transform from marbling mathematics, which conserves area — a point sitting a certain distance from a new drop moves out to exactly the distance that keeps the fluid volume correct. It is a single line of arithmetic, and it is the reason the results look like real marbled endpapers rather than like circles pasted on top of one another. Nothing here is a texture or a filter; every curve you see is where a point of ink genuinely ended up.

Dragging combs the surface instead of dropping into it. Points near your stroke follow it and points further away trail behind, with a smooth falloff so the ink stretches rather than tearing. Short flicks make feathered edges, long slow sweeps pull whole sheets of colour across the pan, and combing back and forth across your own strokes builds the classic nested feather pattern. The comb radius is adjustable, Scatter throws down a fresh handful of drops, and Clear empties the pan. Free in the browser, nothing to install.