What do you mean by "up, down and each" in the list?

What do you mean by "up, down and each" in the list?

A: You mean 1 1 g101page11page: examples of marking and writing methods of construction drawing list by column leveling method? What if it is? This table doesn't say "upper middle class, lower middle class"! Only the middle rib on the B side and the middle rib on the H side. According to your name, it can be called: middle left, middle lower. If so! As shown in Table B, one side rib: 5? 22 (,middle, bottom) means divided by 4? 22 angle steel with a width of 5? 22, and the other side of the width side is also 5? 22 (upper middle). Similarly, the middle rib on the H side: 4? 20 (to the left of the center) means that the height side is 4? 20, and the height of the other side is also 4? 20 (center to right).