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Pong lab  grading scheme

																OBTAINED:
Functionality: 											
10 - ball detects intersections with wall
10 - ball detects intersections with paddle
10 - paddle moves with mouse
10 - paddle detects intersections with walls and moves nicely



Program structure
 5  - all painting is done in a paint method in Pong (which may call methods to draw the ball and the paddle)
10 - painting is done correctly
10 - data encapsulation:  all variables of a class are changed only by methods of that class
  5  - ball moves through move() methods which may be called form outside, but are defined in Ball


Style:
5    -header
10  -comments
10  -easy to understand and verify correctness of the logic
5    -use constants

Extensions:  (extra credit)