Guilloche (Enamel)
Guilloché refers to a technique in which intricate patterns are mechanically engraved into the surface of a metal which is then usually covered with enamel on top giving a distinct aesthetic appearance.
The word originates from France dating back to the 18th century when a French engineer named Guillot invented a tool / turning machine - although this fact and his existence are often debated.
A guilloche enamel silver tray with a pattern that radiates from the centre outwards.
An alternate guilloche design with a complex wavy pattern that radiates from the centre outwards (a pocket clock).