Well, this is slightly lame... I was playing with quadrilateral stellation. I made a cube, deleted the bottom, stellated the top 75%, and stellated the remaining four sides 150%.

I thought the resulting windmill looked somewhat cool and needed something to spin on. I amused myself by spinning it on a penpoint, then made a spike as follows. I created a tetrahedron, deleted all but one face, then stellated it 400%.

After assembling the spike, I taped a paperclip to the summit so the propeller part would have something to rotate on. Moderately cool...

In the next version I want to add some shape construction primitives to make this sort of thing a bit easier...