Building sets are toys that allow children to construct objects from pieces. The most popular building sets are LEGOs, ERECTOR, and CODE. LEGOs are plastic interlocking blocks that come in a variety of shapes and sizes. ERECTOR is a metal construction set that includes nuts, bolts, and girders. CODE is a wooden construction set that includes wooden blocks, dowels, and connectors. All three building sets provide children with the opportunity to explore their creativity and develop problem-solving skills.