So, in 1971, a musical group called Emerson, Lake and Palmer released an album called Tarkus with some cover art that indicated the artist knew his way around a compass (the drawing kind) but had no effing clue about perspective...ahem.
Here's a video of the album. You should be able to see the cover art in the icon, though a quick search for Tarkus on the 'net will show you plenty of copies of the two pictures that exist.
Click to view
Anyway, my work-friend who's into 3D printing has apparently been obsessed with this cover art forever (via his father, because he is far too young to know anything about ELP). Being that there is nothing available on the Internet for him to turn into a 3D model of a Tarkus, he asked me about CAD modeling one.
It was tricky, and it's not perfect, but he was pretty happy with the result:
He has since printed a number of them and is very pleased with them - as is, apparently, his father.