Some interesting mathematics models

Students are happy in doing something interesting and challenging. Here is an interesting model making for them.
A moving sculpture made from paper ...
As I turn this little paper sculpture inside-out, it changes colours.
http://sci-toys.com/scitoys/scitoys/mathematics/paper_ring.html
There is one more model making description on this URL which is called a Geodesic Dome.For more detail click on the above link.