TTL — Through The Lens. A spot-the-difference game in 3D: two scenes you rotate and zoom to compare, with an endless supply of levels generated from a seed.
Two scenes sit side by side — one canonical, one quietly mutated — sharing a single camera, so rotating or zooming moves both at once. Find a difference, press and hold on it, and it heals back into place.
The interesting part is that nobody builds the levels. Each puzzle is generated from a single seed: a base scene is mutated — a prop recoloured, rotated, moved or removed — under spatial and occlusion constraints that keep every difference findable from at least one angle. The generator is pure and renderer-agnostic, so the same seeds can either run live in the browser or be baked into pre-generated levels that ship without the generator.
Around that sits the part that makes it a game: diorama-style walls that fade away as you orbit into them, soft shadows, a toon-shaded look, and a set of hand-crafted environments — a greenhouse, a train station, a detective’s study, an ancient plaza, an attic — that the generator treats as raw material. Written in strict TypeScript on Three.js.
There is a news post with more on the generator.
It stands as a working prototype — one we may yet take further.