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 Ideas Lego Ideas later changed the threshold to include a minimum number of 1,000 votes in the first year after submission or the project would expire, followed by six months to reach 5,000 and then another six months to reach the 10,000 supported votes. Originally, project submissions were allowed to be about anything and had no limits on the size and style of project. After sets began to be rejected with stated reasons, Lego Ideas announced restrictions on content including the use of no new part molds, banning intellectual properties owned by competing toy companies, and adult content. Lego Ideas further