Spirograph was invented by Denys Fisher who first exhibited it at Nuremberg International Toy Fair in 1965, although similar geometric drawing toys had been manufactured before. It was picked up by Kenner for the American market in 1966 and soon became an international phenomenon that is still manufactured today.
The toy consists of a set of plastic gears, rings and straight bars, each surrounded by teeth to enable them to engage with each other. One of the pieces, the stator, is pinned to a piece of paper and another, the rotor, is placed so its teeth engage with the pinned piece, with a pen placed in one of the rotor's holes. The rotor is moved by pushing the pen, creating a curved geometric pattern, technically known as a hypotrochoid (when drawn inside a circle) or epitrochoid (drawn around the outside).
The original game won several awards, including Educational Toy of the Year in the UK, Design Idea of the Month in US Design News magazine and Artistic Toy Oscar in Paris. It was the basis for the Denys Fisher Toys company, which was eventually bought by Hasbro in the 1980s.