Husband has had kidney stone issues for forty years. Use to drive him to the hospital stopping to let him throw up from pain along the way. He has had many lithotripsy and laser procedures to break up the too big to pass ones. Now he passes one three or four times a year with minimal pain. For a while I put them in ziploc bags with the date to compare sizes. Have never seen smooth ones like in the picture-only sharp many-pointed ones. I have thought that the lithotripsy procedures leave tiny particles behind that build into the bigger ones from calcium or oxalate. But only my theory and have heard not a credible one.
Your theory is as good as an scientist’s. Observe, record and postulate....................