Suppose now you want to draw the plans of a box which, let's imagine, is to be 5 inches high, 6 inches wide and 8 inches long. The first thing to do is to draw out a view of the bottom, which also serves as the top since they are alike, and you will have a rectangle like that shown at A in Fig. 48, and mark the dimensions on it, that is, the width and the length of the box. This you do by running a couple of arrows in each direction and marking in the size.

Fig. 48a. The Plan Drawings For A Box

Next draw one of the sides as shown at B and this will give you the height and the length of the box and mark in the sizes, that is 5 and 8 inches accordingly. Finally draw the end and you will have the height and width of the box as shown at C and again you mark in the dimensions.

It is easy to see now that if you have all three dimensions, namely length, breadth and thickness, and that if you make a box in wood or metal it will look like the picture shown at D which is in isometric perspective.

Fig. 48D. The Box Drawn In Isometric Perspective