The business grew well enough. The quacking-duck pull toy became a childhood icon, and Lego prospered until a catastrophic fire burned almost the entire enterprise to ash – a development that put that old woodworker in a less all-wood-inventory frame of mind.
In 1949, Christiansen bought a patent from Kiddicraft, a British firm, for cellulose acetate bricks molded with protruding round studs. That the few shapes were interlocking and universal appealed to the Dane; he envisioned infinite possibilities – for model-building and for the company itself.
Alas, he evidently could see the future in a way the trade could not. Toy stores and consumers themselves were slow to adopt plastic, and Lego struggled against their indifference. A breakthrough came in 1958, when Lego advanced Kiddicraft's technology by molding circular "tubes" into the underside of each brick, vastly increasing their ability to grip the topside studs – what Lego calls "clutch power." But the advance took five years and a new plastic material -- Acrylonitrile Butadiene Styrene -- to fully incoporate.
Only then, in 1963, did the Lego system explode woldwide to become the most ubiquitous toy of the 20th century. (If you divided up all the Lego bricks among everyone in the world, it would amount to 62 apiece.)
The problem was the 21st century. Building blocks are fun, but they have a hard time competing with, say, Playstation. Thus, as the Millennium approached, did Lego contrive to embrace technology with a series of kits called Mindstorms: a combination of Lego blocks, motors, sensors and other components for building programmable tabletop robots. The target: boys 12 and up.