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 and Christian symbolism, among other areas. The term is also applied to other symbols with a threefold shape. A similar shape with four rin ...

), 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 (cinquefoilCinquefoil – Wiktionary
/ref>), or a larger number (multifoil).

Pevsner, Nikolaus Sir Nikolaus Bernhard Leon Pevsner (30 January 1902 – 18 August 1983) was a German-British art historian and architectural historian best known for his monumental 46-volume series of county-by-county guides, ''The Buildings of England'' (1 ...

; 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 became an official department of Yale University in 1961, but it remains financially and operationally autonomous. , Yale Universi ...

, p. 726. Foil motifs may be used as part of the heads and

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

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, rank and pedigree. Armory, the best-known branch ...

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

Gothic Gothic or Gothics may refer to: People and languages *Goths or Gothic people, the ethnonym of a group of East Germanic tribes **Gothic language, an extinct East Germanic language spoken by the Goths **Crimean Gothic, the Gothic language spoken b ...

and

Islamic Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the mai ...

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