This isn't 3D. This is just a flat texture being scaled and moved behind a circular mask. Try setting border-radius to 0. This is interesting, but not novel (people have done far more with just CSS, and I'm betting you could use CSS 3D transforms and transitions to generate actual animated polygons).
If you are a first-year beginner, good work. Keep it up. If not, well, you might have some studying to do.
If you are a first-year beginner, good work. Keep it up. If not, well, you might have some studying to do.