One topic, one beats.json, and a validator that reads it

A narrated paper-collage explainer is assembled from a single file. Its vocabularies are closed: fourteen narrative arcs, nine hook patterns, seven camera moves - and ten more moves banned outright, because an orbit or a crane reads as 3D and tears flat paper. The hook lands in three seconds or the viewer is gone. Shots run 3 to 6 seconds. And no two adjacent beats may share a camera move, which is the rule this whole thing turns on.

The validator is free and needs no account. Paste a beats.json and every enum, duration, hook and move is checked in your browser against the documented vocabulary. Every lane also ships a worked example that costs nothing. Writing a file needs credits.