Except I think these balls are laying still, this is a very nice picture. One of the few depicting rhythm in any kind of way. As a detail, I would have turned over the second ball - and only let balls marked "2" show.. FOr consistency. (9)
I'm not sure if the negative space at the top is necessary, but it doesn't really detract from the shot. I like the concept and I find it interesting that you used balls with different numbers, showing that it obviously was not one ball in motion. I think the lighting should have been better distributed so as to avoid the right side being overexposed, and to avoid the shadows. I enjoyed this shot. 6