A foil is an architectural device based on a symmetrical rendering of leaf shapes, defined by overlapping circles of the same diameter that produce a series of cusps to make a lobe. Typically, the number of cusps can be three (

trefoil A trefoil () is a graphic form composed of the outline of three overlapping rings, used in architecture, Pagan and Christian symbolism, among other areas. The term is also applied to other symbols with a threefold shape. A similar shape with f ...

), four (

quatrefoil A quatrefoil (anciently caterfoil) is a decorative element consisting of a symmetrical shape which forms the overall outline of four partially overlapping circles of the same diameter. It is found in art, architecture, heraldry and traditional ...

), five (cinquefoil), or a larger number (multifoil). Pevsner, Nikolaus; Harris, John: ''The Buildings of England: Lincolnshire'', Penguin (1964); revised by Nicholas Antram (1989),

Yale University Press Yale University Press is the university press of Yale University. It was founded in 1908 by George Parmly Day and Clarence Day, grandsons of Benjamin Day, and became a department of Yale University in 1961, but it remains financially and ope ...

, p. 726. The word comes from Latin ''folium'' which meaning “leaf.” Foil motifs may be used as part of the heads and

tracery Tracery is an architectural device by which windows (or screens, panels, and vaults) are divided into sections of various proportions by stone ''bars'' or ''ribs'' of moulding. Most commonly, it refers to the stonework elements that support th ...

of window lights, complete windows themselves, the underside of arches, in

heraldry Heraldry is a discipline relating to the design, display and study of armorial bearings (known as armory), as well as related disciplines, such as vexillology, together with the study of ceremony, Imperial, royal and noble ranks, rank and genealo ...

, within panelling, and as part of any decorative or ornament device. Foil types are commonly found in Gothic and

Islamic Islam is an Abrahamic religions, Abrahamic monotheistic religion based on the Quran, and the teachings of Muhammad. Adherents of Islam are called Muslims, who are estimated to number Islam by country, 2 billion worldwide and are the world ...

architecture. File:Trefoil-Architectural.svg, Trefoil File:Quatrefoil-Architectural.svg, Quatrefoil File:Chambers 1908 Cinquefoil.png, Cinquefoil

References

Ornaments (architecture) Symbols Heraldic charges Visual motifs {{Architecturalelement-stub