`Choose easy, normal, or blind mode. In easy, two balls move at a time, taking 0.2 seconds to switch, and 30 shuffles. For normal, the balls switch takes 0.15 seconds and 25 shuffles. Just click on the cup that has the marble on it. For blind, the switch time takes 0.25 seconds and 25 shuffles, and you can't really see.
Have fun!