The same principle is true of designs upon the curvilinear plan. The mere repetition of the circle by itself gives us a simple geometric pattern, and we are at liberty to emphasize this circular plan as the main motive; or, as in the case of the rectangular plans, to treat it merely as a basis, and develop free scroll motives upon it; or follow it through its principal variations, as in the ogee, formed by dropping out two intermediate semicircles; or the various forms of the scale arrangement. These simple geometric plans are the most generally useful as plans of designs intended for repetition and extension over space, and they are always safe and sound systems to build upon, since a geometric plan is certain to join comfortably if our measurements are right.

We may, however, often feel that we want something bolder and freer, and start with a motive of sweeping-curves, non-geometric, but even then a certain geometric relation will be necessary, or an equivalent for it, since each curve must be counterbalanced in some way, though not necessarily symmetrically, of course; and even where a square of pattern—say to a wall-paper repeat of twenty-one inches—has been designed, not consciously upon a geometric base, but simply as a composition of lines and masses to repeat, the mechanical conditions of the work when it comes to be printed will supply a certain geometric control, since it necessarily begins in the process of repetition a series of squares of pattern in which the curves are bound to recur in corresponding places. Without a geometric plan of some sort, however, we may easily get into difficulties with awkward leading lines, gaps, or masses, that tumble down, and are only perceived when the paper is printed and hung.

The designer should not feel at all restricted or cramped by his geometric plan, but treat it as an aid and a scaffolding, working in as much variety and richness of detail as he likes, bound only by the necessity of repeating or counterbalancing his forms and lines. In the diagram (p. [131]) the plan of making a repeat less obvious by means of what is termed "a drop" is given, and this system also increases the apparent width of a pattern.

Frieze and Field

The feeling which demands some kind of contrast or relief to a field of repeating pattern, however interesting in itself, seems now almost instinctive. It is felt, too, in the case of plain surfaces, where the eye seeks a moulding to give a little variety or pattern-equivalent in play of light and shadow upon different planes, lines, or concavities and convexities. The common plaster cornice placed to unite walls and ceiling, in our ordinary houses, is a concession (on the part even of the jerriest of builders) to the æsthetic sense. We get the decorated frieze in architecture in obedience to the same demand, though originally a necessary feature of lintel construction, as we have seen, from the days of the festal garland hung around the eaves of the classic house, to its perpetuation in stone in so many varieties.[3] The carved garland depending in a series of graceful curves, or contrasted with pendants, or their rhythm punctuated, as it were, by ox-heads, as on the temple of the Sibyls, Tivoli, formed the needed contrast to the plane masonry of the wall below. Sculptured figures, with the added interest of story, as on the choragic monument of Lysicrates, fulfilled the same decorative function in a more complex and elaborate way.

[3] See "Bases of Design."

To satisfy the same feeling we place a frieze above the patterned field of our modern wall-papers. Such a frieze may be considered as a contrasting border to the pattern of the field, much as the border of a carpet, allowing for difference of material and position; or the frieze may assert itself as the dominant decoration of the room. In this case it would be greater in depth than the simpler bordering type. The interest of the field filling would then be subsidiary, and lead up to the frieze. In wall-paper friezes the difficulty in designing is to think of a motive which will not tire the eye in the necessarily frequent repeats of twenty-one inches. Longer ones have occasionally been produced, the limit being sixty inches. It is often a good plan to recur in the main lines or forms of the frieze to some variation of the lines or forms of the field. If, for instance, the main motive in the field was a vertical scroll design, a horizontal scroll design upon a large scale used for the frieze would answer, the field being kept flat and quiet; or the fan, or radiating shell form, used as a frieze, above a pattern on the scale plan, would be quite harmonious. Relation and balance of line and mass, and arrangement of quantities in such designs, are the chief considerations.

With painting or modelling an artist is freer, as he is at liberty to design a continuous frieze of figures, and introduce as much variety as he chooses.