Houdini Pendulum Drawing

I remember I was amazed with pendulum drawing when I saw it for the first time. This concept is very simple but at a same time the result is pretty complex. Here is the video that shows the result of using this concept using Houdini.

As you can see in the next video, there are two pendulum that are driving a source, emitter. Each pendulum is a sphere that is swinging using RBD Pin Constraint. Then each sphere drive a one end of the IK handle using Rivet. The emitter produce particles which collide and stick to the grid, which is acting as a ground.