Loom is a live material runtime for the web — the thing an AI-generated one-off or a static texture library can’t be: embeddable, reproducible from a seed, and on-brand. Eleven procedural surfaces (terrazzo, marble, risograph, woven fabric, a noise field, cast concrete, hammered metal, troweled plaster, wood grain, glazed tile, pebbled leather) render straight to a DOM element from your design tokens. It is static-first: a material is a surface, not an animation, so Loom renders once and then costs zero frames.

The headline is that it’s non-repeating. Seamless isn’t enough — a seamless tile laid across a hero still shows an obvious grid. tiling: 'stochastic' hex-tiles the seamless unit tile with per-tile random rotation and a variance-preserving blend, so a surface of any size holds a fixed feature size with no visible repeat (the autocorrelation at the tile period drops from 1.0 to ~0.02, contrast intact). No web library does this live — and the same algorithm exports as a three.js shader chunk for 3D.

The materials are theme-aware: an OKLab palette LUT accepts --token references and a MutationObserver recolors the surface when your theme flips, so a Loom background tracks your design tokens instead of hard-coded hex. Any surface can carry story layers — grime, patina, wear that follows the geometry via curvature and occlusion masks, shown live and exported byte-identically.

Beyond the live render, Loom is a verified producer. bake() writes a tileable PNG/WebP; exportPBR() returns a correct map set with true 16-bit height; and exportFor('unity-urp' | 'unreal' | 'godot' | 'three.js') packs the maps to each engine’s own conventions — Unity gets the inverted metallic-smoothness map it actually wants, Unreal a DirectX normal — with a wired .glb, MaterialX, and KTX2 alongside. Every claim is held by a standing 17 CPU + 172 GPU-gate verification harness. Thirty-two presets, deterministic seeds, a graceful 2D fallback, context-loss recovery, and Svelte 5 / React 18+ / vanilla through one mount().