Today kids and adults recognize LEGO, one of the most popular and enduring construction set brands. But many different kinds of construction sets, made of different materials, came before LEGO. The Whitman Publishing Company, a publisher of books but also playthings, produced a building set called Krazy Ikes during the mid-20th century. Sets made in the 1950s were wood, but they changed to plastic during the 1960s. The sets were based on interchangeable pieces with ball joints and sockets, which easily snapped together. Whitman also made a board game, which incorporated the set. The game was appropriate for quite young children, as it did not involve counting or reading.