Tinkertoy play sets appeared in the second decade of the 20th century along with several other (now classic) construction sets designed to introduce children to the world of engineering and mechanics. With these toys, youngsters made the skyscrapers, bridges, towers, carousels and other structures that they saw in their own cities and towns. Tinkertoys were first envisioned by Charles Pajeau, a tombstone cutter and salesman. He fashioned his toys after the pencils and empty wooden spools he saw children use to build abstract forms. Pajeau sized the sticks and spools of his sets using the progressive ratio of right angles, enabling kids to build an infinite number and variety of structures. Pajeau and his company, The Toy Tinkers of Evanston, sold the 81-part set from 1914 to 1927 when they offered a bigger Double Tinkertoy. Many variations of the sets followed in the ensuing years.