We are building a shooter, and I can't imagine any reason why we would want or need a track ball in our pit, or would want to try to launch one in our pit.
I guess if you are building a robot that grips the ball, then you might need one for adjusting things, but then you'd also probably be depending on the trackballs all being the same size/inflation? which is unlikely.
I have a feeling that this game is going to be difficult to demonstrate when we take the robot around to different places to show it off after the season ends
