Geometric series are probably one of the first infinite sums that most of us encountered in high-school. It seemed very strange that even if you keep adding numbers forever you would get a finite answer. In this video Think Twice go over some examples of geometric series and how we can get some insight on why it works by using visuals.
Amazing Chladni Plate Experiment
This is the Chladni plate experiment. Specific frequencies vibrate the metal plate so that it creates beautiful geometric patterns.