Very nice indeed! I especially like the fact that the source is so well annotated, which makes me wonder: why bother with minifying it at all and not simply use the unminified source on Jsfiddle?
// Non-minified source in 35 lines for HN, because it's the latest fad :)
https://www.hnsearch.com/search#request/submissions&q=%2230+...
> Note that the goal here was to make the source code as small as possible, not clarity; so even the original code before minification is a horrible mess. This doesn’t do justice to the elegance and simplicity of proper raytracer code; I’m writing a book to right this wrong.