A surface with no inside.

THE SYSTEM BEHIND THE SURFACE

Inside Soap Film.

Soap Film marches each ray through a spherical shell rather than a filled ball, so the film is crossed twice and every filament keeps one interference order. Inside the shell a domain-warped fold field carries a zero set that reads as a sheet; each step integrates that band exactly along the ray, so folds draw themselves as smooth bright edges without grain. Colour comes from two-beam interference in three wavelength bands: the path difference is 2nd·cos θ, shorter toward the rim, and each band averages its fringes out as the film thickens, so thick film reads white and the rim turns silver and straw instead of rainbow stripes. The outer skin brightens at grazing angles and mirrors a soft window.

Three sampled wavelengths are not a spectrum, and the three palette colours are broad rather than monochromatic, so the band weights are sharpened before mixing to keep a fringe coloured. Drainage is a fixed vertical gradient, not a solved thin-film flow; there is no surfactant model, no rupture, no Plateau borders and no real bubble lifetime. Nothing here is a spectral render or a physically validated optics result.

7.93 ms GPU timestamp median; p95 9.765 ms. 1440x900 @ dpr 1.5; Metal driver on macOS Version 26.6.2 (Build 25G83); measured 2026-09-28. This is a recorded headless sample, not a browser FPS or mobile-performance guarantee.