[Paddles] Add a ball.
[Paddles] Move ball
[Paddles] Bounce
[Paddles] Collide with paddle
[Paddles] Finer-grained physics
[Paddles] Show scores
[Paddles] Allow scoring
[Paddles] Score consistently
[Paddles] Computer player
[Paddles] Decrease speed
[Paddles] Increase ball speed
[Paddles] Perfect strategy?
[Paddles] Prediction inaccuracy
[Paddles] Add velocity change on bounce
[Paddles] Increase difficulty during game
[Paddles] Add dashes to board
[Paddles] Add scene for final score
[Paddles] Show results
[Paddles] Run to score of 7