Like one of your commenters below, I am wondering if you made this just for the challenge.
Light: Seems OK, no problems that I can tell.
Focus: I'm assuming you wanted the edges of the ball to be blurry (out of focus)? On that assumption, I think you did a good job with focus, but, IMHO the contrast between the sharp middle and blurry edges of the ball is a bit much. I think I would have preferred the edges to be slighly more in focus (but that's opinion).
Composition: Again IMO, placing the ball right in the middle of the picture makes for a rather static picture, without much visual interest to hold the viewer's attention.
Overall: I think this was a good idea for office art, and a technically clean shot, but not an exciting picture.
Great idea... this guy at work had a real rubber band ball that he made over several years, out of the rubber bands from the newspapers he'd read at work every day at lunch. 1 rubber band a day. :) Every single rubber band was different! Amazing.
I like the color tones and simple design. Good detail in the center - hard to do, but a little more clarity at the poles would have been better. (btw, you have way too much time on your hands). 7 no 8
This is a fun picture. We used to do this as kids to make bouncy balls. Takes a long time to build a good one. Lighting is appropriate. Usually I don't like exact centered subject matters, but this one is good. I like the DOF you used. Nice detail of the rubber bands. 9 Good luck in the challenge.