I've noticed on several brand of tape measures a small diamond shape that repeats itself approximately every 19 3/16 inches. It is simular to the marking at every 16 inches that indicats a stud wall for layout purposes. However, I'm unaware of what this diamond marking is or who would be the person or trade that it is intended for. It also appears to be eight feet divided into five equal parts. Can you enlighten me as to the purpose and intent of this diamond marking approximately every 19 3/16 inch mark?