Extras

anthemion-konche

A bivalve of relief, opening

The second object on the shelf, after desme, and the pair to iris rather than a repeat of it: that one is a film, one layer thick, and this is a stack. A single film gives a bubble’s pastels; a stack of platelets sharpens the same interference into abalone’s greens and magentas, which is a different picture from a different formula. Here for the shelf’s one test — an opening shell is a thing people photograph — and not Greek, whatever κόγχη means.

Pairs of curved cards, each pair two valves on one hinge, and every valve is a raymarched height field rather than a bump map — so ribs occlude each other in raking light and the rim is a real silhouette. The relief morphs continuously between a shell’s radial costae, abalone’s swirled laminae and a billowing cloud, out of one octave loop rather than three fractals crossfaded. Colour is multi-beam interference off a stack of aragonite platelets, sin²(Nδ/2)/N²sin²(δ/2) over eight wavelengths, and the curve is what makes it move: the view angle sweeps across a curved card, so the band travels as the shell turns, which is the one thing a flat field cannot do. Platelet thickness follows the relief, so the colour runs along the ribs. Inside an <anthemion-sky> the key light is the page’s own hour. Without WebGL it is a pearl centre on a dark ground, and the gradient is on the element itself so it survives having no JavaScript at all.