Cool Paper Toy

This Link is to cool little paper toy. I haven't made it yet, but I'll post a photo when I do.
http://sci-toys.com/scitoys/scitoys/mathematics/paper_ring.html
This is another link to more complex paper structures. http://nuwen.net/poly.html
I don't understand the math behind them, of couse, but I'm sure it's all very interesting.