Sandy E sent along this tip - I know that you can accomplish what I was trying to do with a button, but I don't have 12 of them the same size, or of graduated sizes, so: I was having trouble with an all over design making the stitches, that were getting closer to the center of the design, to all get there at the same time. I used a graph paper program and used polar settings at 1/16 inch apart. Then I cut circles of various sizes, 3, 5, 7, 9, rows each. I pinned one at the center then stitched to it, then pinned the smaller one there and stitched to it. Now all my center sections are the same size on the whole ball.

Since I know that the above description needs a picture -