 FACT: When Robert Graysmith visits Paul Avery at his boathouse you  can see Pong being displayed in the background on Pauls TV. If Paul  had been playing the game in one player mode the paddle on the right  would have been controlled by the computer and it would have been  moving to block the shot. Also 15 is the game point on Pong. Once  this is reached the ball disappears until the game is reset, or if  left for a long enough time it would go into the Demo mode. In demo  mode however there is no sound.