Repetition and Alternation
Generally speaking, the detail should preferably be of a formal character, and should consist of the repetition of units with no interest beyond that imparted by alternation.
The detail must, moreover, be designed with due regard to the space to be filled, and, in any border which encloses any space, a common divisor of height and width should be found in accordance with which the unit can be designed.
Treatment of Angles
No. 207. The Evolute Scroll as a Border.
A. Continuous. B. Reciprocal
The meeting angles or corners of borders invariably require special treatment, and in those positions the detail should be compact and stronger in appearance than the general pattern. The simplest expedient is some form of patera or rosette, but, whatever the detail, it should always be in strong contrast to that of the run of the border. The only forms that can be continuous without any marked change in the angles, are the undulating stem, the wave, and its square form the key or labyrinth; but even with these the proportion of width to height at times needs modification. If a common divisor is not possible, the difficulty can to some extent be overcome by making the form reciprocal and letting the two sides meet in the centre of the border, so that any slight disparity in treatment and dimensions will not be noticeable.