The Tinkertoy Construction Set is a toy construction set for children. It was created in 1914 one year after the A. C. Gilbert Company's Erector Setby Charles H. Pajeau and Robert Pettit in Evanston, Illinois. Pajeau, a stonemason, designed the toy after seeing children play with pencils and empty spools of thread. He and Pettit set out to market a toy that would allow and inspire children to use their imaginations. At first, this did not go well, but after a year or two over a million were sold. The cornerstone of the set is a wooden spool roughly two inches (5 cm) in diameter with holes drilled every 45 degrees around the perimeter and one through the center. Unlike the center, the perimeter holes do not go all the way through. With the differing-length sticks, the set was intended to be based on the Pythagorean progressive right triangle. Tinkertoy sticks before 1992 were made with a diameter of 0.25 inch.
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