3D image rotations with cairo, in C language on Ubuntu, a simple example

some time ago I was shown an example of 3d rotations of image(s) but this example has about 20 different images and in my opinion, is overly complicated. Can anyone point me in the direction of a simple, minimal example that shows only one image rotation of say, a bunch of (x, y, z) points?

Please ignore this, I’ve solved it myself, thanks, Roger.