A spirograph is a drawing toy that allow the user to draw patterns of cyclical curved lines. The original toy consisted of a series of templates and inserts which meshed together using teeth like those of machine gears. The inserts were perforated with a number of holes for accepting a pen or pencil and by holding the instrument down while moving the insert around the inside of the template, a design would gradually take shape as the pen traced its cyclical pattern. The name Spirograph® is a registered trademark of the toy company Hasbro, Inc. and should be capitalized when discussing one of their line of Spirograph® toys. The word spirograph, however was in use before becoming a trademark and has also come to mean any such drawing, or other similar device that creates such patterns and has become a part of the English language as a noun and so is not always capitalized.
The origins of the spirograph as a drawing toy go back to 1908 when a similar device called the Wondergraph, which used a system of gears to produce geometric drawings, was marketed by the Sears and Roebuck Co. It was primarily a wooden device that included a small turntable and wooden stylus. An earlier device also called a spirograph was invented by a French mathematician in the 1880s, but this was primarily a mathematical tool for calculating the area encompassed by certain kinds of curves rather than a toy. The first Spirograph® toy was marketed by Kenner in the United States in 1966.
The original spirograph toy consisted of stators and inserts, both of which are lined with teeth like those on mechanical gears and was designed so that the teeth of each insert meshed with any stator. Stators are templates of various shapes that are placed over the paper and are meant to be stationary during the drawing process. The stators in the original spirograph toy included small holes so that they could be pinned to an underlying layer of cardboard or other surface with paper in between.
The current versions use a magnetic tablet and metal pins to hold the stator. An insert with one or more holes for some type of drawing instrument like a pen or pencil is placed against the stator which may be of several shapes and may accept inserts inside and sometimes on the outside as well. By holding the insert down against the paper as well as against the stator and by using the drawing utensil to move it around the stator, a geometric design of curved lines is created, and by changing the combination of the drawing utensil holes, inserts and stators, an almost infinite variety of designs is possible.
Today, there are many derivative toys based on the original spirograph and they are sold under other names. Additionally, the principle behind the Spirograph®, which creates curves that are describable by mathematic functions and equations is used in devices such as programmable laser projectors for stage lighting. These devices can trace spirograph -like designs on a projection medium like stage smoke or a screen.