Inline windows

A shader block embeds a live WebGL window in the page. Each window has a single play/stop control — stopping rewinds to the start, so play always begins fresh. Here is the built-in shader, set to autoplay:

To present a window stopped on its first frame instead — letting the reader press play to start it — pass :autoplay false:

With JavaScript disabled, shader windows are simply not shown and the page reads normally — the effect is pure progressive enhancement.