The invention of friction toys is credited to D.P. Clark, one of the founding members of the Dayton Group, a loose association of Ohio-based toymakers. Clark patented a friction flywheel system in 1897, the same year he initially organized his Dayton Friction Toy Works. Clark’s design led to the company’s series of popular “Hill Climber” friction toys which were produced through the 1930s. The toys were originally made from tin and wood parts assembled and painted by hand, with models ranging from chauffeur-driven sedans to circus trains.