Perpetuum Mobile

This is called the Cascade method of juggling.  Juggling is good for you.  In this method the number of balls is always odd.  Juggling boosts brain development, so maybe it's a good hobby to take up during a pandemic.  I learned how to juggle on the graveyard shift of a job over 20 years ago.  Memory, focus, movement, and visual acuity all play a part.  Since you have only two hands, if you look closely, it means there is always a ball in the mix that is interstitial.  Play Johann Strauss's classical piece in the title as you watch his willy swing.