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 into larger ones — but reads it through a flat bubble network plus a live height-profile strip on the side that traces the drainage front sinking through the foam over time, making the solitary wave predicted by the foam drainage equation directly visible instead of implied by bubble colour alone.