|
Spirograph2 (cropped)
Spirograph is a geometric drawing device that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. The well-known toy version was developed by British engineer Denys Fisher and first sold in 1965. The name has been a registered trademark of Hasbro Inc. since 1998 following purchase of the company that had acquired the Denys Fisher company. The Spirograph brand was relaunched worldwide in 2013, with its original product configurations, by Kahootz Toys. History In 1827, Greek-born English architect and engineer Peter Hubert Desvignes developed and advertised a "Speiragraph", a device to create elaborate spiral drawings. A man named J. Jopling soon claimed to have previously invented similar methods. When working in Vienna between 1845 and 1848, Desvignes constructed a version of the machine that would help prevent banknote forgeries, as any of the nearly endless variations of roulette patterns that it could produce were ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denys Fisher
Denys Fisher (11 May 1918 – 17 September 2002) was an English engineer who invented the spirograph toy and created the company Denys Fisher Toys. He left Leeds University to join the family firmKingfisher (Lubrication) Ltd In 1960 he left the firm to set up his own company, Denys Fisher Engineering, in Leeds. In 1961 the company won a contract with NATO to supply springs and precision components for its 20 mm cannon. Between 1962 and 1964 he developed various drawing machines from Meccano pieces, eventually producing a prototype Spirograph. Patented in 16 countries, it went on sale in Schofields department store in Leeds in 1965. A year later, Fisher licensed Spirograph to Kenner Products in the United States. In 1967 Spirograph was chosen as the UK Toy of the Year. Denys Fisher Toys, which also produced other toys and board games, was sold to Palitoy in 1970 and it was subsequently bought by Hasbro. Through the 1980s and 1990s Fisher continued to work with Hasbro in dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Various Spirograph Designs
Various may refer to: * Various (band), an English dubstep/electronic music duo * Various artists, a term for a compilation album containing pieces by various musicians * Various authors, a book containing works by several writers * ''The Various'', a children's fantasy novel by Steve Augarde See also * Various & Gould, a Berlin-based artist duo * ''Various Artists – Archives Vol. 4'', an album by Steve Vai * ''Various Failures'', a compilation album by American experimental rock band Swans * ''The Various Haunts of Men'', a novel by Susan Hill * ''Various Positions'', an album by Leonard Cohen ** Various Positions Tour * ''Various Positions'' (film), a 2002 film directed by Ori Kowarsky * Varius (other) Varius is a Latin word meaning "diverse", "different", "changeable", "various" or "variegated" and may refer to: * ''Varius'' (moth), a genus of moths belonging to the small family Nepticulidae * Varius Manx, a Polish pop group * XKO Varius, a we ... * [Baidu] |
Guilloché
Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and repetitive pattern is mechanically engraved into an underlying material via engine turning, which uses a machine of the same name, also called a rose engine lathe. This mechanical technique improved on more time-consuming designs achieved by hand and allowed for greater delicacy, precision, and closeness of line, as well as greater speed. The term ''guilloche'' is also used more generally for repetitive architectural patterns of intersecting or overlapping spirals or other shapes, as used in the Ancient Near East, classical Greece and Rome and neo-classical architecture, and Early Medieval interlace decoration in Anglo-Saxon art and elsewhere. Medieval Cosmatesque stone inlay designs with two ribbons winding around a series of regular central points are very often called guilloche. These central points are often blank, but may contain a figure, such as a rose. These senses are a ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometric Lathe
A geometric lathe was used for making ornamental patterns on the plates used in printing bank notes and postage stamps. It is sometimes called a guilloché lathe. It was developed early in the nineteenth century when efforts were introduced to combat forgery, and is an adaptation of an ornamental turning lathe. The lathe was able to generate intersecting and interlacing patterns of fine lines in various shapes, which were almost impossible to forge by hand-engraving. They were used by many national mints. Further reading *Peter Bower, 'Economic warfare: Banknote Forgery as a deliberate weapon', and Maureen Greenland, 'Compound plate printing and nineteenth-century bank notes, in Virginia Hewitt, ed. ''The Banker's Art: Studies in paper money'', pp 46–63, and pp 84–87, The British Museum Press, 1995, () See also * Security printing * Spirograph * Tusi couple * Guilloché Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and repe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclograph
A cyclograph (also known as an arcograph) is an instrument for drawing arcs of large diameter circles whose centres are inconveniently or inaccessibly located, one version of which was invented by Scottish architect and mathematician Peter Nicholson. Description In his autobiography, published in 1904, polymath Herbert Spencer eloquently describes his own near re-invention of Nicholson's cyclograph while working as a civil engineer for the Birmingham and Gloucester Railway. See also * Spirograph Spirograph is a geometric drawing device that produces mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids. The well-known toy version was developed by British engineer Denys Fisher and first sold in ... References {{reflist, colwidth=30em Technical drawing tools ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apsidal Precession
In celestial mechanics, apsidal precession (or apsidal advance) is the precession (gradual rotation) of the line connecting the apsides (line of apsides) of an astronomical body's orbit. The apsides are the orbital points closest (periapsis) and farthest (apoapsis) from its primary body. The apsidal precession is the first time derivative of the argument of periapsis, one of the six main orbital elements of an orbit. Apsidal precession is considered positive when the orbit's axis rotates in the same direction as the orbital motion. An apsidal period is the time interval required for an orbit to precess through 360°. History The ancient Greek astronomer Hipparchus noted the apsidal precession of the Moon's orbit (as the revolution of the Moon's apogee with a period of approximately 8.85 years); it is corrected for in the Antikythera Mechanism (circa 80 BCE) (with the supposed value of 8.88 years per full cycle, correct to within 0.34% of current measurements). The pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardioid
In geometry, 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. The name was coined by de Castillon in 1741 but the cardioid had been the subject of study decades beforehand.Yates Named for its heart-like form, it is shaped more like the outline of the cross section of a round apple without the stalk. A cardioid microphone exhibits an acoustic pickup pattern that, when graphed in two dimensions, resembles a cardioid (any 2d plane containing the 3d straight line of the microphone body). In three dimensions, the cardioid is shaped like an apple centred around the microphone which is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypocycloid
In geometry, a hypocycloid is a special plane curve generated by the trace of a fixed point on a small circle that rolls within a larger circle. As the radius of the larger circle is increased, the hypocycloid becomes more like the cycloid created by rolling a circle on a line. Properties If the smaller circle has radius , and the larger circle has radius , then the parametric equations for the curve can be given by either: :\begin & x (\theta) = (R - r) \cos \theta + r \cos \left(\frac \theta \right) \\ & y (\theta) = (R - r) \sin \theta - r \sin \left( \frac \theta \right) \end or: :\begin & x (\theta) = r (k - 1) \cos \theta + r \cos \left( (k - 1) \theta \right) \\ & y (\theta) = r (k - 1) \sin \theta - r \sin \left( (k - 1) \theta \right) \end If is an integer, then the curve is closed, and has Cusp (singularity), cusps (i.e., sharp corners, where the curve is not Differentiable function, differentiable). Specially for the curve is a straight line and the circles are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Similarity (geometry)
In Euclidean geometry, two objects are similar if they have the same shape, or one has the same shape as the mirror image of the other. More precisely, one can be obtained from the other by uniformly scaling (geometry), scaling (enlarging or reducing), possibly with additional translation (geometry), translation, rotation (mathematics), rotation and reflection (mathematics), reflection. This means that either object can be rescaled, repositioned, and reflected, so as to coincide precisely with the other object. If two objects are similar, each is congruence (geometry), congruent to the result of a particular uniform scaling of the other. For example, all circles are similar to each other, all squares are similar to each other, and all equilateral triangles are similar to each other. On the other hand, ellipses are not all similar to each other, rectangles are not all similar to each other, and isosceles triangles are not all similar to each other. If two angles of a triangle h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Even And Odd Functions
In mathematics, even functions and odd functions are functions which satisfy particular symmetry relations, with respect to taking additive inverses. They are important in many areas of mathematical analysis, especially the theory of power series and Fourier series. They are named for the parity of the powers of the power functions which satisfy each condition: the function f(x) = x^n is an even function if ''n'' is an even integer, and it is an odd function if ''n'' is an odd integer. Definition and examples Evenness and oddness are generally considered for real functions, that is real-valued functions of a real variable. However, the concepts may be more generally defined for functions whose domain and codomain both have a notion of additive inverse. This includes abelian groups, all rings, all fields, and all vector spaces. Thus, for example, a real function could be odd or even (or neither), as could a complex-valued function of a vector variable, and so on. The given e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resonance Cascade
The Half-Life (series), ''Half-Life'' video game series features many locations set in a dystopian future stemming from the events of the first game, Half-Life (video game), ''Half-Life''. These locations are used and referred to throughout the series. The locations, for the most part, are designed and modeled from real-world equivalent locations in Eastern Europe, but also include science fiction settings including the Black Mesa Research Facility, a labyrinthine subterranean research complex, and Xen, an alien dimension. ''Half-Life'' and expansions Black Mesa Research Facility The Black Mesa Research Facility (shortened to B.M.R.F) is the primary setting for ''Half-Life (video game), Half-Life'' and its three expansions: ''Half-Life: Opposing Force, Opposing Force'', ''Half-Life: Blue Shift, Blue Shift'', and ''Half-Life: Decay, Decay''. The base is a decommissioned Intercontinental ballistic missile, ICBM Missile launch facility, launch complex at an undisclosed New Mexic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballpoint Pen
A ballpoint pen, also known as a biro (British English), ball pen (Hong Kong, Indian and Philippine English), or dot pen ( Nepali) is a pen that dispenses ink (usually in paste form) over a metal ball at its point, i.e. over a "ball point". The metal commonly used is steel, brass, or tungsten carbide. The design was conceived and developed as a cleaner and more reliable alternative to dip pens and fountain pens, and it is now the world's most-used writing instrument; millions are manufactured and sold daily. It has influenced art and graphic design and spawned an artwork genre. Some pen manufacturers produce designer ballpoint pens for the high-end and collectors' markets. History Origins The concept of using a "ball point" within a writing instrument to apply ink to paper has existed since the late 19th century. In these inventions, the ink was placed in a thin tube whose end was blocked by a tiny ball, held so that it could not slip into the tube or fall out of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.JPG "Click for more on -> Spirograph2 (cropped)")
.jpeg/1200px-Bic_(28332699).jpeg "Click for more on -> Ballpoint Pen")