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Click the mouse to create a ball at a point on the screen.
Drag the mouse before letting go to give it an initial velocity in that direction with a magnitude corresponding to how far you drag the mouse.


9 (not on Num Pad) Turn on gravity
0 (not on Num Pad) Turn off gravity
P Create balls with positive charge (yellow)
M Create balls with negative charge (purple)
N Create balls with no charge
R Reset the screen (destroy all balls)
- (not on Num Pad) Make gravity weaker
+ (not on Num Pad) Make gravity stronger
Space Bar Pause the simulation (can still make balls)

Questions, comments, or suggestions? Email me at

Last updated 12/31/08.