Explanation of Flower Ring pictures

These Pan pictures are all from a common motif.  They were inspired by a car wheel cover I saw.  
Begin with a single thin ring.
Then replicate these rings and distribute them regularly around an invisible circle. For instance, here are six of them distributed on an invisible circle of radius 1.5. We're zoomed out further this time.
Finally, crop the whole image, removing everything outside of a disk.  Here is a crop with radius 2.3.
All of the pictures in the set are simply variations of number of rings, ring thickness, distance from center, and cropping radius.  For instance, here are a few more.
See these closely related pictures.
And these ones also.