Interactive jelly hammerhead shark physics study

GOAL: Make an interactive WebGPU soft-body study of a great hammerhead shark cast in two layers of jelly, resting on its belly in a soft photo studio. MOTION: Build it from a signed distance field: an elliptical body section swept along the spine, slim at the neck, deep at the chest, with a slim caudal peduncle. Give it an oversized cephalofoil — a wide, flat hammer whose span is about 40% of the body length, with a nearly straight front edge, a small notch in the middle, ends swept slightly back, full and round at the front and thinning toward the back, with a large glossy eye at each tip. Seven kinds of fin from one recipe (convex leading edge, falcate trailing edge, thinning toward the tip): a very tall sickle-shaped first dorsal, second dorsal, pectorals, tall pelvic fins, anal fin and a lopsided tail with a subterminal notch. Clear tinted jelly over a milky white belly layer that also fills the underside of the hammer; trapped bubbles; a darker back, dusky fin tips, five gill slits, a small crescent mouth with milky teeth, grooves along the front of the hammer and pores beneath it, all drawn in the shader from rest-space coordinates so they stretch with the jelly. Simulate it as an XPBD tetrahedral mesh (snapped hex lattice, co-rotational elasticity, volume preservation, floor friction), with firmer fins. Muscle strain drives two moves: a slow head sweep from side to side, like a metal detector over the sand, and a tail swish. Let the user grab and stretch the jelly, twist with the scroll wheel or a second finger, drop beads of jelly bait, and switch between three colourways (steel, amber, gummy blue). Render with refraction, Beer–Lambert absorption, back-lit glow in the thin parts and tinted shadows. Show live mass, volume, fork length and the distance between the eyes.