Perfectly bouncy balls are delicately stacked. Click on a ball to nudge it a little and see what happens.
The project is done with the pen and a lot of vector math. The bounces are accurate. The collisions are perfectly elastic, so the total energy of the system never decreases. One might say that the potential energy of gravity in the stack is turned into kinetic energy in the bouncing. Gravity is weak in this project. If it is stronger, the balls turn the energy of gravity into kinetic energy and the stack of balls start to bounce on its own. So, do not construct buildings out of perfectly bouncy balls or, equivalently, an ideal gas.
