Educational toy made in plastic versions. In the mid-1950s, more explicitly engineering-themed construction toys appeared, including plastic girders, columns, and panels that could be assembled into a model curtain wall skyscraper. Later, this Girder and Panel structural system was extended to a Hydro-Dynamic setup by adding pipes, valves, tanks, nozzles, and pumps to allow construction of model plumbing, HVAC, and chemical engineering systems like a simulated distillation column. Other extensions of the system supported suburban-style housing developments (Build-A-Home), or monorail transportation systems (Skyrail). The building toy Lego was originally developed by Ole Kirk Christiansen in Billund, Denmark, in the 1930s. The name
The Lego Group Below are historical images of the Lego logo throughout the company's existence. Since the expiration of the last standing Lego patent in 1989, a number of companies have produced interlocking bricks that are similar to Lego bricks. The toy company Tyco Toys produced such bricks for a time; other competitors include Mega Bloks and Best-Lock. These competitor products are typically compatible with Lego bricks, and are often marketed at a lower cost than Lego sets. One such competitor is Coko, manufactured by Chinese company Tianjin Coko Toy Co., Ltd. In 2002, Lego Group's Swiss subsidiary Interlego AG sued the company