I recall a full-page colorful article in the Asbury Park Press that ran many, many, many years ago in which the manufacturing process was described. It is my recollection that the basic chip had squared notches in them and that the colored soft clay inserts were inserted by hand before the chip went to the furnace for baking. I don't believe that a whole sheet would all be the same. Remember, this chip and the article referred to above was back in the 70's. Perhaps the process is different today.