[Illustration: THE EVOLUTION OF A DESIGN INVOLVING THE USE OF TWO HORIZONTAL AND THREE VERTICAL SUBDIVISIONS
The cement bench, Figure 31, has a three-division arrangement to break up the monotony of the long rail, and at the same time to repeat the characteristics of a horizontal primary mass.
[Sidenote: Three Vertical Divisions in Metal]
Figure 33, Plate 14, is a common example of three vertical divisions in metal suggested by the needs of service. Figures 35 and 36 are thin metal problems. The familiar pen tray is primarily a horizontal mass, so determined by its required service as a pen holder. The projecting handles form the outer divisions, and the spacing motive, Rule 3b, has been repeated in the raised projection, decorating the handles. The book rack in Figure 36 is an example of the manner in which a nearly square mass, so designed for structural reasons, may, by Rules 3b and 2a, be broken into a fairly pleasing arrangement of divisions.
Rule 3c. _In elementary problems, if more than three vertical divisions are required, they should be so grouped as to analyze into Rules 3a and 3b, or be exactly similar._ The eye becomes confused by a multitude of vertical divisions and it is much better designing to keep them within the number stated in this chapter. There are instances, however, when this is impossible. Under such conditions the following treatment should be adopted:
Unless, as stated, a large number of vertical divisions may be grouped into two or three vertical divisions it is better to make all of the divisions of the same size. This does not fatigue the eye as much as would the introduction of a number of complex spacings. This solution enables the amateur designer to deal with complex problems with an assurance of securing a degree of unity.
Plate 15 is practically self-explanatory and shows the order in which the various divisions, so far considered, are to be introduced into the design together with the grouping of details within those divisions. Figure D introduces the additional element termed the appendage to be considered in Chapter V.
(_a_) Construction of the rectangle representing the vertical or horizontal character of the primary mass with desirable proportions. Select the most prominent surface for this rectangle, preferably the front elevation.