Guilloché (or Guilloche) is a decorative engraving technique in which a very precise intricate repetitive pattern or design is mechanically engraved into an underlying material with fine detail. Specifically, it involves a technique of engine turning, called guilloché in French after the French engineer “Guillot”, who invented a machine “that could scratch fine patterns and designs on metallic surfaces”. The machine, called a rose engine, improved upon the more time-consuming practice of making similar designs by hand, allowing for greater delicacy, precision, and closeness of the line, as well as greater speed.