You control the demo mainly by left/right dragging the mouse, but some basic, unoptimized support for keyboard navigation is in there as well (Arrow Key/PgUp/PgDn). If you click on a face it will light up briefly and you can now enter a new color in the fields below the canvas.
So this is a sort of update what has happened since then: I’ve actually used TinyDim sometimes and it has received some level of basic optimization at the code level (it’s still missing any structural optimizations like caching or viz-areas), but I never got around to post about it. It now has support for one global light and has its own mouse navigation class for when you just want to view a static 3D model. Support for colored faces is still only hacked in with a proprietary format (although that would be easy to change, you just have to write a MAT file parser) and It can return the face you’ve clicked on.
So, if you want to hack in texture support using this technique or anything else, be my guest