Quincunx
From Wikipedia, the free encyclopedia
A quincunx (IPA ['kwɪnkʌŋks]) is a geometric pattern consisting of five points, four of them forming a square or rectangle and a fifth at its center. It forms the arrangement of five units in the pattern corresponding to the five-spot on dice, playing cards, or dominoes.
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[edit] Historical origins of the name
The quincunx was originally a coin issued by the Roman Republic c.211-200 BC, whose value was five twelfths (quinque + uncia) of an as, the Roman standard bronze coin. On the Roman quincunx coins, the value was sometimes indicated by a pattern of five dots or pellets. However, these dots were not always arranged in a quincunx pattern.
[edit] Examples
Quincunx patterns occur in many contexts:
- In heraldry, groups of five elements (charges) are often arranged in a quincunx pattern, called in saltire in heraldic terminology.
- A quincunx is a standard pattern for planting an orchard.[1]
- Quincunxes are used in modern computer graphics as a supersampling pattern for anti-aliasing. Quincunx antialiasing samples scenes at the corners and centers of each pixel. These five sample points, in the shape of a quincunx, are combined to produce each displayed pixel. However, samples at the corner points are shared with adjacent pixels, so the number of samples needed is only twice the number of displayed pixels. [2]
- In architecture, a quincuncial plan, also defined as a "cross-in-square", is the plan of an edifice composed of nine bays. The central and the four angular ones are covered with domes, barrel vaults or groin vaults; the other four are surmounted by barrel vaults.[3]
- In literature, the English physician Sir Thomas Browne in his philosophical discourse The Garden of Cyrus (1658) elaborates upon evidence of the quincunx pattern in art, nature and mystically as 'evidence' of intelligent design. Lawrence Durrell's novel-sequence The Avignon Quintet is arranged in the form of a quincunx, according to the author; the final novel in the sequence is called Quinx, the plot of which includes the discovery of a quincunx of stones. The Quincunx (ISBN 0-345-37113-5) is the title of a lengthy and elaborate novel by Charles Palliser set in 19th-century England, published in 1989; the pattern appears in the text as a heraldic device, and is also reflected in the structure of the book.
- The points on each face of a unit cell of a face-centred cubic lattice form a quincunx.
- A quincuncial map is a conformal map projection that maps the poles of the sphere to the centre and four corners of a square, thus forming a quincunx.
[edit] Other meanings
The word "quincunx" has other meanings, not referring to a five-point pattern.
Sir Francis Galton designed a machine for demonstrating the normal distribution which is often called a "quincunx"; see bean machine.
In astrology (and less commonly in astronomy), a quincunx (also known as an inconjunct) is an astrological aspect of five-twelfths of a circle, or 150°, between two objects (the Sun, Moon, planets or signs).[4]
In botany, the term quincuncial does not refer to a quincunx, but an entirely different arrangement of flat objects. It has more than one meaning in botany, [5] but the only meaning that is not obscure or extremely rare names a form of aestivation, the arrangement of perianth parts in bud [6]
Some literary uses of the word Quincunx do not seem to be associated with the quincunx shape. Quincunx is the name of the lake with an island containing Mistress Masham's Repose in the novel of that name by T. H. White. James Blish wrote the 1973 novel The Quincunx of Time.
[edit] References
- ^ Gourley, Joseph Harvey (2008), Modern Fruit Production, Read Books, pp. 106–107, ISBN 9781443726061.
- ^ Chambers, Mike (February 27, 2001), "NVIDIA GeForce3 Preview", nV News, http://www.nvnews.net/previews/geforce3/quincunx.shtml.
- ^ R. Krautheimer, Early Christian and Byzantine Architecture, 1965
- ^ Kaler, James B. (2002), The Ever-changing Sky: A Guide to the Celestial Sphere, Cambridge University Press, p. 300, ISBN 9780521499187.
- ^ Benjamin D. Jackson. A Glossary of Botanic Terms. Duckworth: London (1928).
- ^ Glossary in Peter F. Stevens (2001 onwards). Angiosperm Phylogeny Website (see external links, below).
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