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
Lego of Lego's popularity by producing blocks of similar dimensions, and advertising them as being compatible with Lego bricks. In 2002, Lego sued the CoCo Toy Company in Beijing for copyright infringement over its "Coko bricks" product. CoCo was ordered to cease manufacture of the products, publish a formal apology and pay damages. Lego sued the English company Best-Lock Construction Toys in German courts in 2004 and 2009; the Federal Patent Court of Germany denied Lego trademark protection for the shape of its bricks for the latter case. In 2005, the Lego Company sued Canadian company Mega Bloks for trademark violation,