In
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ... , a spiral is a
curve
In mathematics, a curve (also called a curved line in older texts) is an object similar to a line (geometry), line, but that does not have to be Linearity, straight.
Intuitively, a curve may be thought of as the trace left by a moving point (ge ... which emanates from a point, moving farther away as it revolves around the point.
Helices
Two major definitions of "spiral" in the
American Heritage Dictionary are:
Spiral
# a curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point.
# a three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis; a
helix .
The first definition describes a
planar curve, that extends in both of the perpendicular directions within its plane; the groove on one side of a
record
A record, recording or records may refer to:
An item or collection of data Computing
* Record (computer science), a data structure
** Record, or row (database), a set of fields in a database related to one entity
** Boot sector or boot record, ... closely approximates a plane spiral (and it is by the finite width and depth of the groove, but ''not'' by the wider spacing between than within tracks, that it falls short of being a perfect example); note that successive loops ''differ'' in diameter. In another example, the "center lines" of the arms of a
spiral galaxy
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''logarithmic spiral s.
The second definition includes two kinds of 3-dimensional relatives of spirals:
# a conical or volute spring
A volute spring, also known as a conical spring, is a compression spring in the form of a cone (somewhat like the classical volute decorative architectural ornament). Under compression, the coils slide past each other, thus enabling the spring to ... battery box ), and the vortex
In fluid dynamics, a vortex ( : vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in th ... DNA , both of which are quite helical, so that "helix" is a more ''useful'' description than "spiral" for each of them; in general, "spiral" is seldom applied if successive "loops" of a curve have the same diameter.[
In the side picture, the black curve at the bottom is an ]Archimedean spiral
The Archimedean spiral (also known as the arithmetic spiral) is a spiral named after the 3rd-century BC Greek mathematician Archimedes. It is the locus corresponding to the locations over time of a point moving away from a fixed point with a con ... Two-dimensional
A two-dimensional , or plane, spiral may be described most easily using polar coordinates
In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction. The reference point (analogous to the or ... radius
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ... r is a monotonic
In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves or reverses the given order. This concept first arose in calculus, and was later generalized to the more abstract setting of order ... continuous function
In mathematics, a continuous function is a function such that a continuous variation (that is a change without jump) of the argument induces a continuous variation of the value of the function. This means that there are no abrupt changes in value ... \varphi :
* r=r(\varphi)\; .
The circle would be regarded as a degenerate case (the function not being strictly monotonic, but rather constant ).
In ''x -y -coordinates'' the curve has the parametric representation:
* x=r(\varphi)\cos\varphi \ ,\qquad y=r(\varphi)\sin\varphi\; .
Examples
Some of the most important sorts of two-dimensional spirals include:
* The Archimedean spiral
The Archimedean spiral (also known as the arithmetic spiral) is a spiral named after the 3rd-century BC Greek mathematician Archimedes. It is the locus corresponding to the locations over time of a point moving away from a fixed point with a con ... r=a \varphi
* The hyperbolic spiral
A hyperbolic spiral is a plane curve, which can be described in polar coordinates by the equation
:r=\frac
of a hyperbola. Because it can be generated by a circle inversion of an Archimedean spiral, it is called Reciprocal spiral, too..
Pierre ... r = a/ \varphi
* Fermat's spiral
A Fermat's spiral or parabolic spiral is a plane curve with the property that the area between any two consecutive full turns around the spiral is invariant. As a result, the distance between turns grows in inverse proportion to their distance f ... r= a\varphi^
* The lituus : r = a\varphi^
* The logarithmic spiral : r=ae^
* The Cornu spiral
An Euler spiral is a curve whose curvature changes linearly with its curve length (the curvature of a circular curve is equal to the reciprocal of the radius). Euler spirals are also commonly referred to as spiros, clothoids, or Cornu spirals.
E ... Fibonacci spiral
Fibonacci (; also , ; – ), also known as Leonardo Bonacci, Leonardo of Pisa, or Leonardo Bigollo Pisano ('Leonardo the Traveller from Pisa'), was an Italian mathematician from the Republic of Pisa, considered to be "the most talented Western ... golden spiral
In geometry, a golden spiral is a logarithmic spiral whose growth factor is , the golden ratio. That is, a golden spiral gets wider (or further from its origin) by a factor of for every quarter turn it makes.
Approximations of the golden spira ... Spiral of Theodorus
In geometry, the spiral of Theodorus (also called ''square root spiral'', ''Einstein spiral'', ''Pythagorean spiral'', or ''Pythagoras's snail'') is a spiral composed of right triangles, placed edge-to-edge. It was named after Theodorus of Cyrene ... involute
In mathematics, an involute (also known as an evolvent) is a particular type of curve that is dependent on another shape or curve. An involute of a curve is the locus of a point on a piece of taut string as the string is either unwrapped from or ... gear
A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic pr ...
Image:Archimedean spiral.svg, Archimedean spiral
Image:Hyperspiral.svg, hyperbolic spiral
Image:Fermat's spiral.svg, Fermat's spiral
Image:Lituus.svg, lituus
Image:Logarithmic Spiral Pylab.svg, logarithmic spiral
Image:Cornu Spiral.svg, Cornu spiral
Image:Spiral of Theodorus.svg, spiral of Theodorus
Image:Fibonacci_spiral.svg, Fibonacci Spiral (golden spiral)
Image:Archimedean-involute-circle-spirals-comparison.svg, The involute of a circle (black) is not identical to the Archimedean spiral (red).
\varphi=\tfrac\cdot \ln \tfrac . Approximations of this are found in nature.
Spirals which do not fit into this scheme of the first 5 examples:
A ''Cornu spiral'' has two asymptotic points.Involute#Examples .
Geometric properties
The following considerations are dealing with spirals, which can be described by a polar equation r=r(\varphi) , especially for the cases r(\varphi)=a\varphi^n (Archimedean, hyperbolic, Fermat's, lituus spirals) and the logarithmic spiral r=ae^ .
\alpha between the spiral tangent and the corresponding polar circle (see diagram) is called ''angle of the polar slope and \tan \alpha the ''polar slope''.
From vector calculus in polar coordinates one gets the formula
:\tan\alpha=\frac\ .
Hence the slope of the spiral \;r=a\varphi^n \; is
* \tan\alpha=\frac\ .
In case of an ''Archimedean spiral'' (n=1 ) the polar slope is \; \tan\alpha=\tfrac\ .
The ''logarithmic spiral'' is a special case, because of \ \tan\alpha=k\ ''constant'' !
;curvature
The curvature \kappa of a curve with polar equation r=r(\varphi) is
:\kappa = \frac\ .
For a spiral with r=a\varphi^n one gets
* \kappa = \dotsb = \frac\frac\ .
In case of n=1 ''(Archimedean spiral)''
\kappa=\tfrac .-1 the spiral has an ''inflection point''.
The curvature of a ''logarithmic spiral'' \; r=a e^ \; is \; \kappa=\tfrac \; .
;Sector area
The area of a sector of a curve (see diagram) with polar equation r=r(\varphi) is
:A=\frac\int_^ r(\varphi)^2\; d\varphi\ .
For a spiral with equation r=a\varphi^n\; one gets
* A=\frac\int_^ a^2\varphi^\; d\varphi
=\frac\big(\varphi_2^- \varphi_1^\big)\ , \quad \text\quad n\ne-\frac,
:A=\frac\int_^ \frac\; d\varphi
=\frac(\ln\varphi_2-\ln\varphi_1)\ ,\quad \text \quad n=-\frac\ .
The formula for a ''logarithmic spiral'' \; r=a e^ \; is
\ A=\tfrac\ .
;Arc length
The length of an arc of a curve with polar equation r=r(\varphi) is
:L=\int\limits_^\sqrt\,\mathrm\varphi \ .
For the spiral r=a\varphi^n\; the length is
* L=\int_^ \sqrt\; d\varphi
= a\int\limits_^\varphi^\sqrtd\varphi
\ .
Not all these integrals can be solved by a suitable table. In case of a Fermat's spiral the integral can be expressed by elliptic integral s only.
The arc length of a ''logarithmic spiral'' \; r=a e^ \; is \ L=\tfrac\big(r(\varphi_2)-r(\varphi_1)\big) \ .
;Circle inversion
The inversion at the unit circle has in polar coordinates the simple description: \ (r,\varphi) \mapsto (\tfrac,\varphi)\ .
* The image of a spiral \ r= a\varphi^n\ under the inversion at the unit circle is the spiral with polar equation \ r= \tfrac\varphi^\ . For example: The inverse of an Archimedean spiral is a hyperbolic spiral.
:A logarithmic spiral \; r=a e^ \; is mapped onto the logarithmic spiral \; r=\tfrac e^ \; .
Bounded spirals
r(\varphi) of a spiral is usually strictly monotonic, continuous
and unbounded
Boundedness or bounded may refer to:
Economics
* Bounded rationality, the idea that human rationality in decision-making is bounded by the available information, the cognitive limitations, and the time available to make the decision
* Bounded e ... r(\varphi) is either a power function or an exponential function. If one chooses for r(\varphi) a ''bounded'' function the spiral is bounded, too. A suitable bounded function is the arctan
In mathematics, the inverse trigonometric functions (occasionally also called arcus functions, antitrigonometric functions or cyclometric functions) are the inverse functions of the trigonometric functions (with suitably restricted domains). Spec ... \;r=a \arctan(k\varphi)\; and the choice \;k=0.1, a=4, \;\varphi\ge 0\; gives a spiral, that starts at the origin (like an Archimedean spiral) and approaches the circle with radius \;r=a\pi/2\; (diagram, left).
;Example 2
For \;r=a (\arctan(k\varphi)+\pi/2)\; and \;k=0.2, a=2,\; -\infty<\varphi<\infty\; one gets a spiral, that approaches the origin (like a hyperbolic spiral) and approaches the circle with radius \;r=a\pi\; (diagram, right).
Three-dimensional
space curve
In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight.
Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that a ... coiled coil filament
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxidat ... Slinky
The Slinky is a helical spring toy invented by Richard James in the early 1940s. It can perform a number of tricks, including travelling down a flight of steps end-over-end as it stretches and re-forms itself with the aid of gravity and its ow ... Conical spirals
If in the x -y -plane a spiral with parametric representation
:x=r(\varphi)\cos\varphi \ ,\qquad y=r(\varphi)\sin\varphi
is given, then there can be added a third coordinate z(\varphi) , such that the now space curve lies on the cone with equation \;m(x^2+y^2)=(z-z_0)^2\ ,\ m>0\; :
* x=r(\varphi)\cos\varphi \ ,\qquad y=r(\varphi)\sin\varphi\ , \qquad \color \ .
Spirals based on this procedure are called conical spirals.
;Example
Starting with an ''archimedean spiral'' \;r(\varphi)=a\varphi\; one gets the conical spiral (see diagram)
:x=a\varphi\cos\varphi \ ,\qquad y=a\varphi\sin\varphi\ , \qquad z=z_0 + ma\varphi \ ,\quad \varphi \ge 0 \ .
Spherical spirals
If one represents a sphere of radius r by:
:
\begin
x &=& r \cdot \sin \theta \cdot \cos \varphi \\
y &=& r \cdot \sin \theta \cdot \sin \varphi \\
z &=& r \cdot \cos \theta
\end
and sets the linear dependency \; \varphi=c\theta , \; c> 2\; , for the angle coordinates, one gets a spherical curve
A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ce ... c equal to twice the number of turns)
*
\begin
x &=& r \cdot \sin \theta \cdot \cos \\
y &=& r \cdot \sin \theta \cdot \sin \\
z &=& r \cdot \cos \theta\qquad \qquad 0\le\theta\le \pi \ .
\end
Spherical spirals were known to Pappus, too.
Remark: a rhumb line
In navigation, a rhumb line, rhumb (), or loxodrome is an arc crossing all meridians of longitude at the same angle, that is, a path with constant bearing as measured relative to true north.
Introduction
The effect of following a rhumb li ...
KUGSPI-5 Archimedische Kugelspirale.gif, Spherical spiral
KUGSPI-9_Loxodrome.gif, Loxodrome
A rhumb line
In navigation, a rhumb line, rhumb (), or loxodrome is an arc crossing all meridians of longitude at the same angle, that is, a path with constant bearing as measured relative to true north.
Introduction
The effect of following a rhumb li ... bearing (e.g., travelling from one pole to the other while keeping a fixed angle
In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle.
Angles formed by two ... meridians ). The loxodrome has an infinite number of revolution
In political science, a revolution (Latin: ''revolutio'', "a turn around") is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolts against the government, typically due ... Archimedean spiral
The Archimedean spiral (also known as the arithmetic spiral) is a spiral named after the 3rd-century BC Greek mathematician Archimedes. It is the locus corresponding to the locations over time of a point moving away from a fixed point with a con ... In nature
The study of spirals in nature
Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ... Christopher Wren
Sir Christopher Wren PRS FRS (; – ) was one of the most highly acclaimed English architects in history, as well as an anatomist, astronomer, geometer, and mathematician-physicist. He was accorded responsibility for rebuilding 52 churches ... shells form a logarithmic spiral ; Jan Swammerdam
Jan Swammerdam (February 12, 1637 – February 17, 1680) was a Dutch biologist and microscopist. His work on insects demonstrated that the various phases during the life of an insect—egg, larva, pupa, and adult—are different forms of the ... Helix '' to ''Spirula
''Spirula spirula'' is a species of deep-water squid-like cephalopod mollusc, mollusk. It is the only extant taxon, extant member of the genus ''Spirula'', the Family (biology), family Spirulidae, and the order (biology), order Spirulida. Because ... Henry Nottidge Moseley
Henry Nottidge Moseley Fellow of the Royal Society, FRS (14 November 1844 – 10 November 1891) was a British natural history, naturalist who sailed on the global scientific expedition of Challenger expedition, HMS ''Challenger'' in 1872 through ... univalve
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. ... D’Arcy Wentworth Thompson
Sir D'Arcy Wentworth Thompson CB FRS FRSE (2 May 1860 – 21 June 1948) was a Scottish biologist, mathematician and classics scholar. He was a pioneer of mathematical and theoretical biology, travelled on expeditions to the Bering Strait an ... On Growth and Form '' gives extensive treatment to these spirals. He describes how shells are formed by rotating a closed curve around a fixed axis: the shape
A shape or figure is a graphics, graphical representation of an object or its external boundary, outline, or external Surface (mathematics), surface, as opposed to other properties such as color, Surface texture, texture, or material type.
A pl ... geometric progression . In some shells, such as '' Nautilus '' and ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ... helico -spiral pattern. Thompson also studied spirals occurring in horn
Horn most often refers to:
*Horn (acoustic), a conical or bell shaped aperture used to guide sound
** Horn (instrument), collective name for tube-shaped wind musical instruments
*Horn (anatomy), a pointed, bony projection on the head of various ... teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ... claw s and plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ... floret
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ... sunflower
The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ... \theta = n \times 137.5^,\ r = c \sqrt
where ''n'' is the index number of the floret and ''c'' is a constant scaling factor, and is a form of Fermat's spiral
A Fermat's spiral or parabolic spiral is a plane curve with the property that the area between any two consecutive full turns around the spiral is invariant. As a result, the distance between turns grows in inverse proportion to their distance f ... golden angle
In geometry, the golden angle is the smaller of the two angles created by sectioning the circumference of a circle according to the golden ratio; that is, into two arcs such that the ratio of the length of the smaller arc to the length of the l ... golden ratio and gives a close packing of florets.
Spirals in plants and animals are frequently described as whorls
A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs).
Whorls in nature
File:Photograph and axial plane floral d ... fingerprint
A fingerprint is an impression left by the friction ridges of a human finger. The recovery of partial fingerprints from a crime scene is an important method of forensic science. Moisture and grease on a finger result in fingerprints on surfac ...
The center Galaxy of Cat's Eye.jpg, An artist's rendering of a spiral galaxy.
Helianthus whorl.jpg, Sunflower head displaying florets in spirals of 34 and 55 around the outside.
As a symbol
A spiral like form has been found in Mezine
Mezine is a place within the modern country of Ukraine which has the most artifact finds of Paleolithic culture origin. The Epigravettian site is located on a bank of the Desna River in Novhorod-Siverskyi Raion of Chernihiv Oblast, northern Ukrain ... Ukraine
Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ... triple spiral motif is a Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ... Megalithic Temples of Malta
The Megalithic Temples of Malta ( mt, It-Tempji Megalitiċi ta' Malta) are several prehistoric temples, some of which are UNESCO World Heritage Sites, built during three distinct periods approximately between 3600 BC and 2500 BC on the island coun ... Celtic
Celtic, Celtics or Keltic may refer to:
Language and ethnicity
*pertaining to Celts, a collection of Indo-European peoples in Europe and Anatolia
**Celts (modern)
*Celtic languages
**Proto-Celtic language
* Celtic music
*Celtic nations
Sports Fo ... Newgrange
Newgrange ( ga, Sí an Bhrú) is a prehistoric monument in County Meath in Ireland, located on a rise overlooking the River Boyne, west of Drogheda. It is an exceptionally grand passage tomb built during the Neolithic Period, around 3200 BC, ... County Meath
County Meath (; gle, Contae na Mí or simply ) is a county in the Eastern and Midland Region of Ireland, within the province of Leinster. It is bordered by Dublin to the southeast, Louth to the northeast, Kildare to the south, Offaly to the sou ... Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ... triskelion
A triskelion or triskeles is an ancient motif consisting of a triple spiral exhibiting rotational symmetry.
The spiral design can be based on interlocking Archimedean spirals, or represent three bent human legs. It is found in artefacts of ... Mycenaean vessels, on coinage in Lycia
Lycia (Lycian language, Lycian: 𐊗𐊕𐊐𐊎𐊆𐊖 ''Trm̃mis''; el, Λυκία, ; tr, Likya) was a state or nationality that flourished in Anatolia from 15–14th centuries BC (as Lukka) to 546 BC. It bordered the Mediterranean ... stater s of Pamphylia (at Aspendos
Aspendos or Aspendus ( Pamphylian: ΕΣΤϜΕΔΥΣ; Attic: Ἄσπενδος) was an ancient Greco-Roman city in Antalya province of Turkey. The site is located 40 km east of the modern city of Antalya.
It was situated on the Eurymedon ... Pisidia , as well as on the heraldic
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 branc ... petroglyphs
A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ... Las Plazuelas , Guanajuato
Guanajuato (), officially the Free and Sovereign State of Guanajuato ( es, Estado Libre y Soberano de Guanajuato), is one of the 32 states that make up the Federal Entities of Mexico. It is divided into 46 municipalities and its capital city i ... Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ... Nazca Lines in the coastal desert of Peru, dating from 200 BC to 500 AD. The geoglyphs
A geoglyph is a large design or motif (generally longer than 4 metres) produced on the ground by durable elements of the landscape, such as stones, stone fragments, gravel, or earth. A positive geoglyph is formed by the arrangement and alignmen ... swastika
The swastika (卐 or 卍) is an ancient religious and cultural symbol, predominantly in various Eurasian, as well as some African and American cultures, now also widely recognized for its appropriation by the Nazi Party and by neo-Nazis. It ... triskele
A triskelion or triskeles is an ancient motif consisting of a triple spiral exhibiting rotational symmetry.
The spiral design can be based on interlocking Archimedean spirals, or represent three bent human legs. It is found in artefacts of ... solar symbol s.
Roof tiles dating back to the Tang Dynasty
The Tang dynasty (, ; zh, t= ), or Tang Empire, was an Dynasties in Chinese history, imperial dynasty of China that ruled from 618 to 907 AD, with an Zhou dynasty (690–705), interregnum between 690 and 705. It was preceded by the Sui dyn ... Chang'an
Chang'an (; ) is the traditional name of Xi'an. The site had been settled since Neolithic times, during which the Yangshao culture was established in Banpo, in the city's suburbs. Furthermore, in the northern vicinity of modern Xi'an, Qin Shi ... hypnosis , stemming from the cliché
A cliché ( or ) is an element of an artistic work, saying, or idea that has become overused to the point of losing its original meaning or effect, even to the point of being weird or irritating, especially when at some earlier time it was consi ... Kaa
Kaa is a fictional character from ''The Jungle Book'' stories written by Rudyard Kipling. He is a giant snake who is 30 feet long.
In the books and many of the screen adaptations, Kaa is an ally of main protagonist Mowgli, acting as a friend a ... The Jungle Book
''The Jungle Book'' (1894) is a collection of stories by the English author Rudyard Kipling. Most of the characters are animals such as Shere Khan the tiger and Baloo the bear, though a principal character is the boy or "man-cub" Mowgli, ... dizziness
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Dizziness is a common medical c ... anime
is Traditional animation, hand-drawn and computer animation, computer-generated animation originating from Japan. Outside of Japan and in English, ''anime'' refers specifically to animation produced in Japan. However, in Japan and in Japane ... manga
Manga (Japanese: 漫画 ) are comics or graphic novels originating from Japan. Most manga conform to a style developed in Japan in the late 19th century, and the form has a long prehistory in earlier Japanese art. The term ''manga'' is u ... double helix of DNA and as large as a galaxy
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ... dialectic
Dialectic ( grc-gre, διαλεκτική, ''dialektikḗ''; related to dialogue; german: Dialektik), also known as the dialectical method, is a discourse between two or more people holding different points of view about a subject but wishing ... Dialectical monism
Dialectical monism, also known as dualistic monism or monistic dualism, is an ontological position that holds that reality is ultimately a unified whole, distinguishing itself from monism by asserting that this whole necessarily expresses itself in ... In art
The spiral has inspired artists throughout the ages. Among the most famous of spiral-inspired art is Robert Smithson 's earthwork , "Spiral Jetty
''Spiral Jetty'' is an earthwork sculpture constructed in April 1970 that is considered to be the most important work of American sculptor Robert Smithson. Smithson documented the construction of the sculpture in a 32-minute color film also tit ... Great Salt Lake
The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, particula ... Balloon Museum in Albuquerque, as well as in the critically acclaimed Nine Inch Nails
Nine Inch Nails, commonly abbreviated as NIN and stylized as NIИ, is an American industrial rock band formed in Cleveland in 1988. Singer, songwriter, multi-instrumentalist, and producer Trent Reznor was the only permanent member of the band ... The Downward Spiral ''. The Spiral is also a prominent theme in the anime Gurren Lagann , where it represents a philosophy and way of life. It also central in Mario Merz and Andy Goldsworthy's work. The spiral is the central theme of the horror manga '' Uzumaki '' by Junji Ito , where a small coastal town is afflicted by a curse involving spirals. ''2012 A Piece of Mind By Wayne A Beale'' also depicts a large spiral in this book of dreams and images. The coiled spiral is a central image in Australian artist Tanja Stark's Suburban Gothic iconography, that incorporates spiral electric stove top elements as symbols of domestic alchemy and spirituality. See also
*Celtic maze
Celtic mazes are straight-line spiral key patterns that have been drawn all over the world since prehistoric times. The patterns originate in early Celtic developments in stone and metal-work, and later in medieval Insular art. Prehistoric spiral ... Concentric circles
* DNA
* Fibonacci number
* Hypogeum of Ħal-Saflieni
*Megalithic Temples of Malta
The Megalithic Temples of Malta ( mt, It-Tempji Megalitiċi ta' Malta) are several prehistoric temples, some of which are UNESCO World Heritage Sites, built during three distinct periods approximately between 3600 BC and 2500 BC on the island coun ... Patterns in nature
*Seashell surface
In mathematics, a seashell surface is a surface made by a circle which spirals up the ''z''-axis while decreasing its own radius and distance from the ''z''-axis. Not all seashell surfaces describe actual seashells found in nature.
Parametriza ... Spirangle
* Spiral vegetable slicer
*Spiral stairs
Stairs are a structure designed to bridge a large vertical distance between lower and higher levels by dividing it into smaller vertical distances. This is achieved as a diagonal series of horizontal platforms called steps which enable passage ... Triskelion
A triskelion or triskeles is an ancient motif consisting of a triple spiral exhibiting rotational symmetry.
The spiral design can be based on interlocking Archimedean spirals, or represent three bent human legs. It is found in artefacts of ... References
Related publications
* Cook, T., 1903. ''Spirals in nature and art''. Nature 68 (1761), 296.
* Cook, T., 1979. ''The curves of life''. Dover, New York.
* Habib, Z., Sakai, M., 2005. ''Spiral transition curves and their applications''. Scientiae Mathematicae Japonicae 61 (2), 195 – 206.
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* Harary, G., Tal, A., 2011. ''The natural 3D spiral''. Computer Graphics Forum 30 (2), 237 – 24 External links
Jamitzer Jamnitzer, Jamnitzer Archimedes' spiral transforms into Galileo's spiral. Mikhail Gaichenkov, OEIS
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Two major definitions of "spiral" in the American Heritage Dictionary are:Spiral
An ''Archimedean spiral'' is, for example, generated while coiling a carpet.
A ''hyperbolic spiral'' appears as image of a helix with a special central projection (see diagram). A hyperbolic spiral is some times called ''reciproke'' spiral, because it is the image of an Archimedean spiral with a circle-inversion (see below).
The name ''logarithmic spiral'' is due to the equation . Approximations of this are found in nature.
Spirals which do not fit into this scheme of the first 5 examples:
A ''Cornu spiral'' has two asymptotic points.
;Polar slope angle
The angle between the spiral tangent and the corresponding polar circle (see diagram) is called ''angle of the polar slope and the ''polar slope''.
From vector calculus in polar coordinates one gets the formula
:
Hence the slope of the spiral is
*
In case of an ''Archimedean spiral'' () the polar slope is
The ''logarithmic spiral'' is a special case, because of ''constant'' !
;curvature
The curvature of a curve with polar equation is
:
For a spiral with one gets
*
In case of ''(Archimedean spiral)''
.