The Laws of Light: Snell, Reflection, and Diffraction as Wave-Matching Folding to Unison

One axiom. One operation. Zero free parameters. The laws of light — Snell’s refraction, reflection at equal angles, diffraction, interference — are taught as separate rules. This paper forces their unifying principle from the fold. Every law of optics is a statement of wave-matching: at a boundary the phases on the two sides must agree, and the wave-matching condition folds to unison (the half-One closing on the One). Refraction is phase-matching across an interface (Snell’s law); reflection is the symmetric match (equal angles); interference and diffraction are the deterministic summation of matched waves — opposed paths cancel (dark), aligned paths survive (bright), the same deterministic discrete account that resolves the double-slit. One principle: phases match, the matching folds to one. Machine-checked; reproduces from one command. A standalone result within the Smithian Fold Theory of Everything (SFTOE). Full corpus, code, and the run-it-yourself VERIFY.md protocol: https://github.com/MettaMazza/Smithian-Fold-Theory