Just smack that flag. No controls needed. The pattern on screen is a visual representation of Pi - each colour corresponds to a digit. In the sound that plays, each note also corresponds to a digit, and it will keep playing for 125,000 notes (because it is running at 5 notes per second, that means it will take 6 hours, 56 minutes and 40 seconds to fully run).
(Am I a bit late for Pi day 2018?)
