In my first tools-for-games class, we had a project to get to know the bare-bones basics, involving making things exclusively out of polygon primitives. I'd made a donut-planet, and wondered later if I'd ever be good enough at Maya to make a fully fledged, textured, sculpted version with convincing oceans, clouds, lands.
Now, for my final Sketchfab Project for Modeling II, I believe I've achieved a passable shot at doing just that. I'd tried other things, but they required things I couldn't figure out at the time, including atmospheric effects and shaders.
So, I eventually decided to give the donut-world thing a try, since I'd already learned quite a bit about the theory of real donut worlds (In theory, not impossible - just very, very improbable!). The fast spin and its effects on gravity and weather patterns, the scrunching vs rifting of continents moving inwards or outwards, the massive seizmic activity of tidal drag slowly collapsing the world into a regular spheroid, etc.