Guilloches
An intricate geometrical pattern formed by superposition of several relatively simple fine curved lines, constructed according to certain mathematical laws. A similar guilloche cannot be constructed without these mathematical laws. Guilloche designs form rosettes, frames, borders, vignettes and other images, as well as the elements of background patterns. A pattern can consist of either negative or positive lines (fig. 1).
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Fig. 1. Negative and positive guilloches.
500 Burundi Francs (1988)