Setup: A double pendulum is constructed using two bob connected by massless, rigid rods.  The red bob has the a larger mass.

Observations:

• Because the red bob's larger mass, it has more gravitational potential energy it is able to transfer enough energy to the green bob to make it go in a complete circle around the red bob.
• The motion is complex enough that the motion of the bob's do not repeat themself like a simple pendulm.