quincunx

The spots on the fifth side of a (playing) die form a quincunx.

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.

A Roman aes grave quincunx coin.

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.

Examples

Quincunx patterns occur in many contexts:

The flag of the Solomon Islands features a quincunx of stars.

A quincuncial map.

• In heraldry, groups of five elements (charges) are often arranged in a quincunx pattern, called in saltire in heraldic terminology. The flag of the Solomon Islands features this pattern, as did the flag of the Republic of Yucatán.
• 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]
• Séamus Heaney describes Ireland's provinces together forming a quincunx, as the Irish word for province cúige (literally: "fifth part") also explicates. The five provinces of Ireland are Ulster (north), Leinster (east), Connacht (west), Munster (south) and Meath (the center). Meath is noted for secular Tara, the central government, and Uisneach (the Irish omphalos, or belly button), being a more sacred place where Ail na Míreann, which means "stone of divisions" was located, and upon which the quincunx of the provinces was inscribed.
• 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.

• The points on each face of a unit cell of a face-centred cubic lattice form a quincunx.

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.

• James Joyce uses the term in 'Grace' a short story in The Dubliners of 1914.

Notes and references

1. ^ Gourley, Joseph Harvey (2008), Modern Fruit Production, Read Books, pp. 106–107, ISBN 9781443726061 .
2. ^ Chambers, Mike (February 27, 2001), "NVIDIA GeForce3 Preview", nV News, http://www.nvnews.net/previews/geforce3/quincunx.shtml .
3. ^ R. Krautheimer, Early Christian and Byzantine Architecture, 1965

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External links

• Botanic Glossary