This was scan of soap bubbles, I then made a square selection and used the polar cordinates filter on it twice, rotating the image between the two applications.

I think I have decided how to finish my Celtic frescoe fragment now. It is worked on top of a piece of felt so I will apply that to a background fabric and do the hand stitching through both layers. Then the background fabric will be laced onto the mounting board. I want it to look like a fragment of painted wall in the end. I think this might do it.