This is a simulation of a basketball on a tilted floor. You can hit the basketball with the hand and you can tilt the floor to a different angle by clicking on it and dragging up or down. How it works: The basketball has variables for speed in the x and y directions. The stage sends gravity messages that periodically accelerate the ball downward. When the ball hits a surface the x and y speeds are reflected according to the rules of trigonometry, and the speed is reduced by a decay factor. When the hand moves across the ball, the speed of movement of the hand in the x and y directions is detected and applied as an acceleration to the ball. To do: change the values of gravityx and gravityy in the stage and restart to see how this affects the behavior of the ball. Can you create "flubber"?