Struck Film

A soap-thin film over a sphere that something keeps striking. Four wave packets are in flight at once — each launched from a hashed point on the surface, expanding as a geodesic ring and decaying as it spreads — and their ripples add to an fbm thickness field that a cosine interference triple turns into rainbow wavefronts. The screen-space derivative of that thickness picks out the creases where colliding fronts crowd, and that is what the glint rides on.