Construction sets are as simple as a pile of rectangular blocks and as intricate as sets designed to replicate Frank Lloyd Wright's Falling Waters and Guggenheim Museum. Child experts have long known that the importance of construction sets is in what kids make of them--literally. Using building sets requires imagination, creativity, planning, critical thinking, and strategizing--all skills that kids will rely on when they enter the adult world. Since the 19th century, toy makers have tried to produce a better construction set. The wooden blocks were succeeded by such 20th-century classics as Tinkertoys, Lincoln Logs, Erector Sets, LEGOs, K'NEX, and others.