Plush Hedgehog Soft-Body Interaction Simulation

A single-file WebGPU "material study" page called "Plush Hedgehog": a button-nosed plush hedgehog with pink cheeks that you can pick up, squash, throw and comb. When it gets shy, it curls into a prickly ball and rolls, then unrolls and stands up again once it stops. The long prompt specifies SDF modeling, XPBD soft-body physics, a second rest shape for curling, and hundreds of soft felt spines over shell fur. Well suited to WebGPU soft-body physics demos and cute pet-interaction short videos.