In mathematics, a **spiral** is a curve which emanates from a point, moving farther away as it revolves around the point.^{ [1] }^{ [2] }^{ [3] }^{ [4] }

Two major definitions of "spiral" in the American Heritage Dictionary are:^{ [5] }

- 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 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 trace logarithmic spirals.

The second definition includes two kinds of 3-dimensional relatives of spirals:

- a conical or volute spring (including the spring used to hold and make contact with the negative terminals of AA or AAA batteries in a battery box), and the vortex that is created when water is draining in a sink is often described as a spiral, or as a conical helix.
- quite explicitly, definition 2 also includes a cylindrical coil spring and a strand of 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.^{ [5] }

In the side picture, the black curve at the bottom is an Archimedean spiral, while the green curve is a helix. The curve shown in red is a conic helix.

A two-dimensional, or plane, spiral may be described most easily using polar coordinates, where the radius is a monotonic continuous function of angle :

The circle would be regarded as a degenerate case (the function not being strictly monotonic, but rather constant).

In *--coordinates* the curve has the parametric representation:

Some of the most important sorts of two-dimensional spirals include:

- The Archimedean spiral:
- The hyperbolic spiral:
- Fermat's spiral:
- The lituus:
- The logarithmic spiral:
- The Cornu spiral or
*clothoid* - The Fibonacci spiral and golden spiral
- The Spiral of Theodorus: an approximation of the Archimedean spiral composed of contiguous right triangles
- The involute of a circle, used twice on each tooth of almost every modern gear

- Archimedean spiral
- hyperbolic spiral
- Fermat's spiral
- lituus
- logarithmic spiral
- Cornu spiral
- spiral of Theodorus
- Fibonacci Spiral (golden spiral)
- The involute of a circle (black) is not identical to the Archimedean spiral (red).

An *Archimedean spiral* is, for example, generated while coiling a carpet.^{ [6] }

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).^{ [7] }

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.

The *spiral of Theodorus* is a polygon.

The *Fibonacci Spiral* consists of a sequence of circle arcs.

The *involute of a circle* looks like an Archimedean, but is not: see Involute#Examples.

The following considerations are dealing with spirals, which can be described by a polar equation , especially for the cases (Archimedean, hyperbolic, Fermat's, lituus spirals) and the logarithmic spiral .

- 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)*.

Only for the spiral has an *inflection point*.

The curvature of a *logarithmic spiral* is

- Sector area

The area of a sector of a curve (see diagram) with polar equation is

For a spiral with equation one gets

The formula for a *logarithmic spiral* is

- Arc length

The length of an arc of a curve with polar equation is

For the spiral the length is

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 integrals only.

The arc length of a *logarithmic spiral* is

- Circle inversion

The inversion at the unit circle has in polar coordinates the simple description: .

- The image of a spiral under the inversion at the unit circle is the spiral with polar equation . For example: The inverse of an Archimedean spiral is a hyperbolic spiral.

- A logarithmic spiral is mapped onto the logarithmic spiral

The function of a spiral is usually strictly monotonic, continuous and unbounded. For the standard spirals is either a power function or an exponential function. If one chooses for a *bounded* function the spiral is bounded, too. A suitable bounded function is the arctan function:

- Example 1

Setting and the choice gives a spiral, that starts at the origin (like an Archimedean spiral) and approaches the circle with radius (diagram, left).

- Example 2

For and one gets a spiral, that approaches the origin (like a hyperbolic spiral) and approaches the circle with radius (diagram, right).

Two well-known spiral space curves are *conic spirals* and *spherical spirals*, defined below. Another instance of space spirals is the *toroidal spiral*.^{ [8] } A "a spiral wound around a helix",^{ [9] } also known as *double-twisted helix*,^{ [10] } represents objects such as coiled coil filaments or the Slinky spring toy.

If in the --plane a spiral with parametric representation

is given, then there can be added a third coordinate , such that the now space curve lies on the cone with equation :

Spirals based on this procedure are called **conical spirals**.

- Example

Starting with an *archimedean spiral* one gets the conical spiral (see diagram)

If one represents a sphere of radius by:

and sets the linear dependency for the angle coordinates, one gets a spherical curve called **spherical spiral**^{ [11] } with the parametric representation (with equal to twice the number of turns)

Spherical spirals were known to Pappus, too.

Remark: a rhumb line is *not* a spherical spiral in this sense.

- Spherical spiral
- Loxodrome

A rhumb line (also known as a loxodrome or "spherical spiral") is the curve on a sphere traced by a ship with constant bearing (e.g., travelling from one pole to the other while keeping a fixed angle with respect to the meridians). The loxodrome has an infinite number of revolutions, with the separation between them decreasing as the curve approaches either of the poles, unlike an Archimedean spiral which maintains uniform line-spacing regardless of radius.

The study of spirals in nature has a long history. Christopher Wren observed that many shells form a logarithmic spiral; Jan Swammerdam observed the common mathematical characteristics of a wide range of shells from * Helix * to * Spirula *; and Henry Nottidge Moseley described the mathematics of univalve shells. D’Arcy Wentworth Thompson's * 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 of the curve remains fixed but its size grows in a geometric progression. In some shells, such as * Nautilus * and ammonites, the generating curve revolves in a plane perpendicular to the axis and the shell will form a planar discoid shape. In others it follows a skew path forming a helico-spiral pattern. Thompson also studied spirals occurring in horns, teeth, claws and plants.^{ [12] }^{[ page needed ]}

A model for the pattern of florets in the head of a sunflower ^{ [13] } was proposed by H. Vogel. This has the form

where *n* is the index number of the floret and *c* is a constant scaling factor, and is a form of Fermat's spiral. The angle 137.5° is the golden angle which is related to the golden ratio and gives a close packing of florets.^{ [14] }

Spirals in plants and animals are frequently described as whorls. This is also the name given to spiral shaped fingerprints.

- An artist's rendering of a spiral galaxy.
- Sunflower head displaying florets in spirals of 34 and 55 around the outside.

A spiral like form has been found in Mezine, Ukraine, as part of a decorative object dated to 10,000 BCE.^{[ citation needed ]}

The spiral and triple spiral motif is a Neolithic symbol in Europe (Megalithic Temples of Malta). The Celtic symbol the triple spiral is in fact a pre-Celtic symbol.^{ [15] } It is carved into the rock of a stone lozenge near the main entrance of the prehistoric Newgrange monument in County Meath, Ireland. Newgrange was built around 3200 BCE predating the Celts and the triple spirals were carved at least 2,500 years before the Celts reached Ireland but has long since been incorporated into Celtic culture.^{ [16] } The triskelion symbol, consisting of three interlocked spirals or three bent human legs, appears in many early cultures, including Mycenaean vessels, on coinage in Lycia, on staters of Pamphylia (at Aspendos, 370–333 BC) and Pisidia, as well as on the heraldic emblem on warriors' shields depicted on Greek pottery.^{ [17] }

Spirals can be found throughout pre-Columbian art in Latin and Central America. The more than 1,400 petroglyphs (rock engravings) in Las Plazuelas, Guanajuato Mexico, dating 750-1200 AD, predominantly depict spirals, dot figures and scale models.^{ [18] } In Colombia monkeys, frog and lizard like figures depicted in petroglyphs or as gold offering figures frequently includes spirals, for example on the palms of hands.^{ [19] } In Lower Central America spirals along with circles, wavy lines, crosses and points are universal petroglyphs characters.^{ [20] } Spirals can also be found among the Nazca Lines in the coastal desert of Peru, dating from 200 BC to 500 AD. The geoglyphs number in the thousands and depict animals, plants and geometric motifs, including spirals.^{ [21] }

Spiral shapes, including the swastika, triskele, etc., have often been interpreted as solar symbols.^{[ citation needed ]} Roof tiles dating back to the Tang Dynasty with this symbol have been found west of the ancient city of Chang'an (modern-day Xi'an).^{[ citation needed ]}^{[ year needed ]}

Spirals are also a symbol of hypnosis, stemming from the cliché of people and cartoon characters being hypnotized by staring into a spinning spiral (one example being Kaa in Disney's * The Jungle Book *). They are also used as a symbol of dizziness, where the eyes of a cartoon character, especially in anime and manga, will turn into spirals to show they are dizzy or dazed. The spiral is also found in structures as small as the double helix of DNA and as large as a galaxy. Because of this frequent natural occurrence, the spiral is the official symbol of the World Pantheist Movement.^{ [22] } The spiral is also a symbol of the dialectic process and Dialectical monism.

The spiral has inspired artists throughout the ages. Among the most famous of spiral-inspired art is Robert Smithson's earthwork, "Spiral Jetty", at the Great Salt Lake in Utah.^{ [23] } The spiral theme is also present in David Wood's Spiral Resonance Field at the Balloon Museum in Albuquerque, as well as in the critically acclaimed Nine Inch Nails 1994 concept album * 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.^{ [24] }^{[ full citation needed ]}^{ [25] }^{[ verification needed ]} 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.^{ [26] }^{ [27] }

**Euler's formula**, named after Leonhard Euler, is a mathematical formula in complex analysis that establishes the fundamental relationship between the trigonometric functions and the complex exponential function. Euler's formula states that for any real number x:

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 is called the *pole*, and the ray from the pole in the reference direction is the *polar axis*. The distance from the pole is called the *radial coordinate*, *radial distance* or simply *radius*, and the angle is called the *angular coordinate*, *polar angle*, or *azimuth*. Angles in polar notation are generally expressed in either degrees or radians.

In mathematics and physics, **Laplace's equation** is a second-order partial differential equation named after Pierre-Simon Laplace, who first studied its properties. This is often written as

A **logarithmic spiral**, **equiangular spiral**, or **growth spiral** is a self-similar spiral curve that often appears in nature. The first to describe a logarithmic spiral was Albrecht Dürer (1525) who called it an "eternal line". More than a century later, the curve was discussed by Descartes (1638), and later extensively investigated by Jacob Bernoulli, who called it *Spira mirabilis*, "the marvelous spiral".

In physics, the **Navier–Stokes equations** are certain partial differential equations which describe the motion of viscous fluid substances, named after French engineer and physicist Claude-Louis Navier and Anglo-Irish physicist and mathematician George Gabriel Stokes. They were developed over several decades of progressively building the theories, from 1822 (Navier) to 1842–1850 (Stokes).

The **Archimedean 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 constant speed along a line that rotates with constant angular velocity. Equivalently, in polar coordinates (*r*, *θ*) it can be described by the equation

An **ellipsoid** is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation.

A **hyperbolic spiral** is a plane curve, which can be described in polar coordinates by the equation

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 from the spiral center, contrasting with the Archimedean spiral and the logarithmic spiral. Fermat spirals are named after Pierre de Fermat.

In mathematics, the **Jacobi elliptic functions** are a set of basic elliptic functions. They are found in the description of the motion of a pendulum, as well as in the design of electronic elliptic filters. While trigonometric functions are defined with reference to a circle, the Jacobi elliptic functions are a generalization which refer to other conic sections, the ellipse in particular. The relation to trigonometric functions is contained in the notation, for example, by the matching notation for . The Jacobi elliptic functions are used more often in practical problems than the Weierstrass elliptic functions as they do not require notions of complex analysis to be defined and/or understood. They were introduced by Carl Gustav Jakob Jacobi (1829). Carl Friedrich Gauss had already studied special Jacobi elliptic functions in 1797, the lemniscate elliptic functions in particular, but his work was published much later.

A **cardioid** is a plane curve traced by a point on the perimeter of a circle that is rolling around a fixed circle of the same radius. It can also be defined as an epicycloid having a single cusp. It is also a type of sinusoidal spiral, and an inverse curve of the parabola with the focus as the center of inversion. A cardioid can also be defined as the set of points of reflections of a fixed point on a circle through all tangents to the circle.

In geometry, a **nephroid** is a specific plane curve whose name means 'kidney-shaped'.

In mathematics, a **Clélie** or **Clelia curve** is a curve on a sphere with the property:

In mathematics, **Viviani's curve**, also known as **Viviani's window**, is a figure eight shaped space curve named after the Italian mathematician Vincenzo Viviani. It is the intersection of a sphere with a cylinder that is tangent to the sphere and passes through two poles of the sphere. Before Viviani this curve was studied by Simon de La Loubère and Gilles de Roberval.

In geometry, the **tangential angle** of a curve in the Cartesian plane, at a specific point, is the angle between the tangent line to the curve at the given point and the x-axis.

The **goat problem** is either of two related problems in recreational mathematics involving at least figuratively a tethered goat grazing a circular area: the interior grazing problem and the exterior grazing problem. The former involves grazing the interior of a circular area, and the latter, grazing the exterior of a circular area.

In geometry, the **sinusoidal spirals** are a family of curves defined by the equation in polar coordinates

In geometry, a **sectrix of Maclaurin** is defined as the curve swept out by the point of intersection of two lines which are each revolving at constant rates about different points called **poles**. Equivalently, a sectrix of Maclaurin can be defined as a curve whose equation in biangular coordinates is linear. The name is derived from the trisectrix of Maclaurin, which is a prominent member of the family, and their sectrix property, which means they can be used to divide an angle into a given number of equal parts. There are special cases known as **arachnida** or **araneidans** because of their spider-like shape, and **Plateau curves** after Joseph Plateau who studied them.

For a plane curve *C* and a given fixed point *O*, the **pedal equation** of the curve is a relation between *r* and *p* where *r* is the distance from *O* to a point on *C* and *p* is the perpendicular distance from *O* to the tangent line to *C* at the point. The point *O* is called the *pedal point* and the values *r* and *p* are sometimes called the *pedal coordinates* of a point relative to the curve and the pedal point. It is also useful to measure the distance of *O* to the normal even though it is not an independent quantity and it relates to as .

In mathematics, a **conical spiral**, also known as a **conical helix**, is a space curve on a right circular cone, whose floor plan is a plane spiral. If the floor plan is a logarithmic spiral, it is called *conchospiral*.

- ↑ "Spiral | mathematics".
*Encyclopedia Britannica*. Retrieved 2020-10-08. - ↑ "Spiral Definition (Illustrated Mathematics Dictionary)".
*www.mathsisfun.com*. Retrieved 2020-10-08. - ↑ "spiral.htm".
*www.math.tamu.edu*. Retrieved 2020-10-08. - ↑ "Math Patterns in Nature".
*The Franklin Institute*. 2017-06-01. Retrieved 2020-10-08. - 1 2 "Spiral,
*American Heritage Dictionary of the English Language*, Houghton Mifflin Company, Fourth Edition, 2009. - ↑ Weisstein, Eric W. "Archimedean Spiral".
*mathworld.wolfram.com*. Retrieved 2020-10-08. - ↑ Weisstein, Eric W. "Hyperbolic Spiral".
*mathworld.wolfram.com*. Retrieved 2020-10-08. - ↑ von Seggern, D.H. (1994).
*Practical Handbook of Curve Design and Generation*. Taylor & Francis. p. 241. ISBN 978-0-8493-8916-0 . Retrieved 2022-03-03. - ↑ "Slinky -- from Wolfram MathWorld".
*Wolfram MathWorld*. 2002-09-13. Retrieved 2022-03-03. - ↑ Ugajin, R.; Ishimoto, C.; Kuroki, Y.; Hirata, S.; Watanabe, S. (2001). "Statistical analysis of a multiply-twisted helix".
*Physica A: Statistical Mechanics and Its Applications*. Elsevier BV.**292**(1–4): 437–451. Bibcode:2001PhyA..292..437U. doi:10.1016/s0378-4371(00)00572-0. ISSN 0378-4371. - ↑ Kuno Fladt:
*Analytische Geometrie spezieller Flächen und Raumkurven*, Springer-Verlag, 2013, ISBN 3322853659, 9783322853653, S. 132 - ↑ Thompson, D'Arcy (1942) [1917].
*On Growth and Form*. Cambridge : University Press ; New York : Macmillan. - ↑ Ben Sparks. "Geogebra: Sunflowers are Irrationally Pretty".
- ↑ Prusinkiewicz, Przemyslaw; Lindenmayer, Aristid (1990).
*The Algorithmic Beauty of Plants*. Springer-Verlag. pp. 101–107. ISBN 978-0-387-97297-8. - ↑ Anthony Murphy and Richard Moore,
*Island of the Setting Sun: In Search of Ireland's Ancient Astronomers,*2nd ed., Dublin: The Liffey Press, 2008, pp. 168-169 - ↑ "Newgrange Ireland - Megalithic Passage Tomb - World Heritage Site". Knowth.com. 2007-12-21. Archived from the original on 2013-07-26. Retrieved 2013-08-16.
- ↑ For example, the trislele on Achilles' round shield on an Attic late sixth-century
*hydria*at the Boston Museum of Fine Arts, illustrated in John Boardman, Jasper Griffin and Oswyn Murray,*Greece and the Hellenistic World*(Oxford History of the Classical World) vol. I (1988), p. 50. - ↑ "Rock Art Of Latin America & The Caribbean" (PDF). International Council on Monuments & Sites. June 2006. p. 5. Archived (PDF) from the original on 5 January 2014. Retrieved 4 January 2014.
- ↑ "Rock Art Of Latin America & The Caribbean" (PDF). International Council on Monuments & Sites. June 2006. p. 99. Archived (PDF) from the original on 5 January 2014. Retrieved 4 January 2014.
- ↑ "Rock Art Of Latin America & The Caribbean" (PDF). International Council on Monuments & Sites. June 2006. p. 17. Archived (PDF) from the original on 5 January 2014. Retrieved 4 January 2014.
- ↑ Jarus, Owen (14 August 2012). "Nazca Lines: Mysterious Geoglyphs in Peru". LiveScience. Archived from the original on 4 January 2014. Retrieved 4 January 2014.
- ↑ Harrison, Paul. "Pantheist Art" (PDF). World Pantheist Movement. Retrieved 7 June 2012.
- ↑ Israel, Nico (2015).
*Spirals : the whirled image in twentieth-century literature and art*. New York Columbia University Press. pp. 161–186. ISBN 978-0-231-15302-7. - ↑ 2012 A Piece of Mind By Wayne A Beale
- ↑ http://www.blurb.com/distribution?id=573100/#/project/573100/project-details/edit (subscription required)
- ↑ Stark, Tanja (4 July 2012). "Spiral Journeys : Turning and Returning".
*tanjastark.com*. - ↑ Stark, Tanja. "Lecture : Spiralling Undercurrents: Archetypal Symbols of Hurt, Hope and Healing".
*Jung Society Melbourne*.

- 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. - Dimulyo, Sarpono; Habib, Zulfiqar; Sakai, Manabu (2009). "Fair cubic transition between two circles with one circle inside or tangent to the other".
*Numerical Algorithms*.**51**(4): 461–476. Bibcode:2009NuAlg..51..461D. doi:10.1007/s11075-008-9252-1. S2CID 22532724. - Harary, G., Tal, A., 2011.
*The natural 3D spiral*. Computer Graphics Forum 30 (2), 237 – 246 . - Xu, L., Mould, D., 2009.
*Magnetic curves: curvature-controlled aesthetic curves using magnetic fields*. In: Deussen, O., Hall, P. (Eds.), Computational Aesthetics in Graphics, Visualization, and Imaging. The Eurographics Association . - Wang, Yulin; Zhao, Bingyan; Zhang, Luzou; Xu, Jiachuan; Wang, Kanchang; Wang, Shuchun (2004). "Designing fair curves using monotone curvature pieces".
*Computer Aided Geometric Design*.**21**(5): 515–527. doi:10.1016/j.cagd.2004.04.001. - Kurnosenko, A. (2010). "Applying inversion to construct planar, rational spirals that satisfy two-point G2 Hermite data".
*Computer Aided Geometric Design*.**27**(3): 262–280. arXiv: 0902.4834 . doi:10.1016/j.cagd.2009.12.004. S2CID 14476206. - A. Kurnosenko.
*Two-point G2 Hermite interpolation with spirals by inversion of hyperbola*. Computer Aided Geometric Design, 27(6), 474–481, 2010. - Miura, K.T., 2006.
*A general equation of aesthetic curves and its self-affinity*. Computer-Aided Design and Applications 3 (1–4), 457–464 . - Miura, K., Sone, J., Yamashita, A., Kaneko, T., 2005.
*Derivation of a general formula of aesthetic curves*. In: 8th International Conference on Humans and Computers (HC2005). Aizu-Wakamutsu, Japan, pp. 166 – 171 . - Meek, D.S.; Walton, D.J. (1989). "The use of Cornu spirals in drawing planar curves of controlled curvature".
*Journal of Computational and Applied Mathematics*.**25**: 69–78. doi: 10.1016/0377-0427(89)90076-9 . - Thomas, Sunil (2017). "Potassium sulfate forms a spiral structure when dissolved in solution".
*Russian Journal of Physical Chemistry B*.**11**(1): 195–198. Bibcode:2017RJPCB..11..195T. doi:10.1134/S1990793117010328. S2CID 99162341. - Farin, Gerald (2006). "Class a Bézier curves".
*Computer Aided Geometric Design*.**23**(7): 573–581. doi:10.1016/j.cagd.2006.03.004. - Farouki, R.T., 1997.
*Pythagorean-hodograph quintic transition curves of monotone curvature*. Computer-Aided Design 29 (9), 601–606. - Yoshida, N., Saito, T., 2006.
*Interactive aesthetic curve segments*. The Visual Computer 22 (9), 896–905 . - Yoshida, N., Saito, T., 2007.
*Quasi-aesthetic curves in rational cubic Bézier forms*. Computer-Aided Design and Applications 4 (9–10), 477–486 . - Ziatdinov, R., Yoshida, N., Kim, T., 2012.
*Analytic parametric equations of log-aesthetic curves in terms of incomplete gamma functions*. Computer Aided Geometric Design 29 (2), 129—140 . - Ziatdinov, R., Yoshida, N., Kim, T., 2012.
*Fitting G2 multispiral transition curve joining two straight lines*, Computer-Aided Design 44(6), 591—596 . - Ziatdinov, R., 2012.
*Family of superspirals with completely monotonic curvature given in terms of Gauss hypergeometric function*. Computer Aided Geometric Design 29(7): 510–518, 2012 . - Ziatdinov, R., Miura K.T., 2012.
*On the Variety of Planar Spirals and Their Applications in Computer Aided Design*. European Researcher 27(8-2), 1227—1232 .

- Jamnitzer -Galerie: 3D-Spirals
- Archimedes' spiral transforms into Galileo's spiral. Mikhail Gaichenkov, OEIS

This page is based on this Wikipedia article

Text is available under the CC BY-SA 4.0 license; additional terms may apply.

Images, videos and audio are available under their respective licenses.

Text is available under the CC BY-SA 4.0 license; additional terms may apply.

Images, videos and audio are available under their respective licenses.