spirograph

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (April 2009)

Several Spirograph designs drawn with a Spirograph set.

Evolution of a typical Spirograph pattern.

Example of a Spirograph set

Spirograph is a geometric drawing toy that produces mathematical curves of the variety technically known as hypotrochoids and epitrochoids. The term has also been used to describe a variety of software applications that display similar curves, and applied to the class of curves that can be produced with the drawing equipment (so in this sense it may be regarded as a synonym of hypotrochoid). The name is a registered trademark of Hasbro, Inc. ^[1]

History

The Spirograph was invented by British engineer Denys Fisher who exhibited it in 1965 at the Nuremberg International Toy Fair. It was subsequently produced by his company. Distribution rights were acquired by Kenner, Inc., which introduced it to the United States' market in 1966.

Operation

A Spirograph consists of a set of plastic gears and other shapes such as rings, triangles, or straight bars. There are several sizes of gears and shapes, and all edges have teeth to engage any other piece. For instance, smaller gears fit inside the larger rings, but also can engage the outside of the rings in such a fashion that they rotate around the inside or along the outside edge of the rings.

To use it, a sheet of paper is placed on a heavy cardboard backing, and one of the plastic pieces—known as a stator—is pinned to the paper and cardboard. Another plastic piece—called the rotor—is placed so that its teeth engage with those of the pinned piece. For example, a ring may be pinned to the paper and a small gear placed inside the ring – the actual number of arrangements possible by combining different gears is very large. The point of a pen is placed in one of the holes of the rotor. As the rotor is moved, the pen traces out a curve.

The pen is used both to draw and provide locomotive force; some practice is required before Spirograph can be operated without disengaging the stator and rotor. More intricate and unusual-shaped patterns may be made through the use of both hands, one to draw and one to guide the pieces. It is possible to move several pieces in relation to each other (say, the triangle around the ring, with a circle "climbing" from the ring onto the triangle), but this requires concentration or even additional assistance from other artists.

In popular culture

• In the Simpsons episode "Radioactive Man," Bart encounters a lonely man in an abandoned Spirograph factory while looking for Milhouse. The man says to Bart: "Wait! Did you know that there's a direct correlation between the decline of Spirograph and the rise in gang activity? Think about it."^[2]

References

See also

• Epicycloid
• Guilloché
• Harmonograph
• Spirograph Nebula, a planetary nebula that displays delicate, spirograph-like filigree.
• Bruno Abakanowicz

External links

• Spirograph in Java
• Weisstein, Eric W., "Spirograph" from MathWorld.
• Spirograph Toy Collection - Collection with photos of many versions including UK and Australian issues.
• Spirograph source files in C#
• Plotting Spirograph equations with gnuplot