Thank you, I will experiment with a reduction in the velocities though I am not convinced that will help regarding the "jumpiness" I am seeing. I have taken the randomness out and am just manipulating 3 circles of equal size but I still see the circles move in unexpected ways occasionally upon collision, ie. the wrong angle or with a much larger velocity. I am curious about the approximation you mention. How is it an approximation? I wonder if making it more exact would help.