I had one that was gappy [dead spots] in its growth, and wasn't pretty at all. I fragged in in half, and the ripple curves of its skeleton nested one in the other, so I glued them that way. I got the idea from having seen one fox the size of a small beachball: and it was indeed a ball, with many layers.
From iffy, immediately after fragging and giving it some breadth, it went to luxuriant. It sits in the rocks at the bottom of my tank, and thrives. My theory is that if it's a single row, it can't feed well; but if it's a multiple row, its ruffles are supported by other ruffles, and it feeds well, being much more able to trap food. This is its second year in my tank, and it's bigger than before.