Guilloche

A pattern or ornament of interlaced curving bands in the form of two or more bands or strings twisting over each other, so as to repeat the same figure, in a continued series by the spiral returning of the bands; sometimes giving the effect of a braid, but most often in smooth curves forming circles. Sometimes considered a type of fret or a type of interlace. Named after the French engineer Guillot, who invented a machine that could scratch fine patterns and designs on metallic surfaces.