What symmetry is to form, that is repetition in the art of ornament. Greek art and Gothic alike have series, with repetition or counterchange for their ruling motive. It is hardly necessary to draw the distinction between this motive and that of the Japanese. The Japanese motives may be defined as uniqueness and position. And these were not known as motives of decoration before the study of Japanese decoration. Repetition and counterchange, of course, have their place in Japanese ornament, as in the diaper patterns for which these people have so singular an invention, but here, too, uniqueness and position are the principal inspiration. And it is quite worth while, and much to the present purpose, to call attention to the chief peculiarity of the Japanese diaper patterns, which is _interruption_. Repetition there must necessarily be in these, but symmetry is avoided by an interruption which is, to the Western eye, at least, perpetually and freshly unexpected. The place of the interruptions of lines, the variation of the place, and the avoidance of correspondence, are precisely what makes Japanese design of this class inimitable. Thus, even in a repeating pattern, you have a curiously successful effect of impulse. It is as though a separate intention had been formed by the designer at every angle. Such renewed consciousness does not make for greatness. Greatness in design has more peace than is found in the gentle abruptness of Japanese lines, in their curious brevity. It is scarcely necessary to say that a line, in all other schools of art, is long or short according to its place and purpose; but only the Japanese designer so contrives his patterns that the line is always short; and many repeating designs are entirely composed of this various and variously-occurring brevity, this prankish avoidance of the goal. Moreover, the Japanese evade symmetry, in the unit of their repeating patterns, by another simple device--that of numbers. They make a small difference in the number of curves and of lines. A great difference would not make the same effect of variety; it would look too much like a contrast. For example, three rods on one side and six on another would be something else than a mere variation, and variety would be lost by the use of them. The Japanese decorator will vary three in this place by two in that, and a sense of the defeat of symmetry is immediately produced. With more violent means the idea of symmetry would have been neither suggested nor refuted.