Physics. The slice is a lattice of 1,386 tetrahedra solved with XPBD (extended position-based dynamics) at a fixed 120 Hz step with 5 substeps. Each tetrahedron carries two constraints in the stable Neo-Hookean style: one resists change of shape, one holds its volume. Rind elements are about twice as stiff as the flesh.
Damping acts only on the rate of deformation, so the slice can swing freely while its wobble dies away. A fine surface mesh, the seeds and the air bubbles are bound to the tetrahedra by barycentric weights, so they bend and turn with the jelly.
Rendering. Native WebGPU and WGSL. A back-face pass measures how much jelly each view ray crosses; light is absorbed along that path (Beer–Lambert), so thin edges glow while the thick heart turns deep ruby. The scene behind is refracted with slight dispersion, Fresnel mixes in reflections of three studio softboxes, and a top-down height pass bakes a soft, tinted contact shadow.