How Do The Swinging Sticks In Iron Man 2 Work

In the movie Iron Man 2 on pepper pots Desk Is A sort of pendulum swinging motion machine.These Are Called sticks.If you look up swinging sticks you find one site you think geek That thesis sells for over $ 200. That Seemed a little expensive so i would like to know how THEY work or how to to Even Better make 'em.