Foam Drainage — Plateau Borders & Laplace Pressure (2D)

This 2D companion drives the same Voronoi-foam drainage model as the 3D version — Laplace pressure P = γ/r pushing liquid between neighbouring bubbles, gravity pulling it downward, and film rupture below a critical thickness merging bubbles — but reads it as a flat network plus a live height-profile strip that traces the drainage front sinking through the foam over time, making the foam drainage equation's solitary wave directly visible instead of implied by bubble colour alone.