The third basic principle of design that should be used in preliminary design is rhythm. Whereas order and unity deal with the overall organization of a design and the relationship of the elements within that organization, rhythm in a composition addresses the factors of time and movement. When we experience a design, whether it be a two-dimensional graphic layout or a three-dimensional spatial composition, as is

the case in residential site design, we do so over a period of time. But we rarely see and experience a complete landscape design instantaneously.

We tend to view various portions of a composition in sequence, often mentally collecting them to form patterns. It is the spacing and timing of these patterns that give a design a dynamic, changing quality. This might be understood more easily by think­ing of rhythm in music. Here, rhythm is formed by the underlying sequence of notes, often referred to as the beat. The beat is a recognizable pattern that provides a dynamic structure to a musical piece and influences the timing of how we experience the music. Among numerous possibilities, it may be slow and casual or rapid and forceful.

Four ways rhythm can be created in residential site design are repetition, alter­nation, inversion, and gradation.

Repetition The principle of repetition as it applies to rhythm differs slightly from the use of repetition for unity. To develop rhythm, repetition is used by repeating elements or a group of elements within a design to create an obvious sequence. For example, Figure 9—29 shows four different examples of elements repeated in linear sequences. In each, the eye moves from element to element in a rhythmic pattern, like the beat in music. In these examples, the spacing between the elements determines the character and pace of the rhythm. In residential site design, this principle applies to such ele­ments as pavement, fences, walls, and plant materials (Figure 9—30). Again, the spacing of elements in these examples is critical in establishing the pace of the rhythm.

Alternation The second type of rhythm is alternation. To create this, it is easiest to first establish a sequential pattern based on repetition. Then, certain elements of the sequence are changed or altered on a regular basis (Figure 9—31). Thus, a rhythmic pattern based on alternation has more variation and sometimes more visual interest than one based only on repetition. The altered elements can furnish an aspect of sur­prise and relief in the sequence. As with repetition for unity, repetition for rhythm can get to be rather monotonous if it is overused. Figure 9—32 shows how alternation has been incorporated in the examples shown previously in Figure 9—30.

Inversion Inversion is a particular type of alternation in which selected elements are changed so their characteristics are in contrast to the initial elements of the sequence. In other words, the altered elements are inverted in comparison with the other elements. Big becomes small, wide becomes narrow, tall changes to short, and so on. Consequently, the


Figure 9-33

Inversion in the pavement pattern, fence heights, wall frame, and shrub masses creates visual rhythm.

changes that occur in this type of sequence can be dramatic and noticeable. Inversion can be incorporated in a landscape design in various ways (Figure 9—33).

Gradation Gradation is created by a gradual change in one or more characteristics of the repeated element of the sequence. For example, the repeated element in a rhythmic sequence may slowly increase in size (Figures 9—34 and 9—35). Or the characteristics of color, texture, and form may also vary as the sequence progresses. The change that oc­curs in gradation provides visual stimulation, but without causing sudden or incongru­ous relationships among the elements of the composition.

Figure 9-34

Rhythm can be established by means of a grad­ual increase in the size of the design elements in a sequence.

As can be seen from the previous sections, the design principles of order, unity, and rhythm can have a direct influence on the visual qualities of a design. They affect the location of elements in a composition as well as the size, form, color, and texture of the elements. During preliminary design, the designer should constantly keep these principles in mind when making key decisions about the appearance of the design. Like other aids in design, design principles are only helpful guidelines that should be carefully applied. They are not recipes for design success.