Snow Globe: 2D Particle-Pile Physics

This 2D companion turns the snow globe into a working granular-accumulation model rather than a fixed decoration: each flake falls under gravity, drifts on a wind term, and loses energy to air resistance exactly as in the 3D version, but instead of resting on a flat floor it packs into a real heightmap-based pile that follows the curve of the glass — denser where flakes land more often, capped so it can never overflow the sphere. Shaking pulls roughly a third of the settled pile back into the air with an upward kick, and a live readout tracks how many flakes are airborne versus packed into the pile, their average speed, and the countdown to the next automatic shake, so the physics behind the "toy" is visible rather than implied.