A sheet of mathematical paper marbling. Pigment drops settle onto a paper-white bath, each color assigned by chance operations. Tap to lay a drop; drag a stylus to comb the surface into feathered patterns; press and hold for concentric suminagashi rings of alternating ink and paper. Operations: stone lays lone drops, rings lays wandering circles, combed adds slow automatic tine sweeps. Rehang starts a new numbered piece; save downloads the current one.