Yet, curiously, if the instructor said nothing to the student about any of this, but continually threw the big flat-washer for the student with the same side always facing down, and if its surface had been smooth and unblemished initially, then after the student had hit the washer the first time, his second hit would generally be within a millimeter of his first hit on the washer, and his third hit would fall within a millimeter of the first two hits. But if neither McDaniel nor his assistant could see any of the BB dents in the spinning washers, then it was a fairly safe bet that few if any of their students could see them either.