Battery   Recorder   Matrix  Player 2 Change window four times, each after some time: Next window = 2nd gray button Hints: Change synchronously with Player 1. Look for him making a sign for the change. You are going to change to windows Player 1 just played before, like in a canon. Listen to what he does while you go after him. Try to copy some of his ideas. After the 4th change, the same windows as in the beginning will be played.