Lego Technic is a line of Lego interconnecting plastic rods and parts. The purpose of this series is to create more advanced models with more complex technical functions, compared to the simpler brick-building properties of normal LEGO.The concept was introduced as the Expert Builder series and originally Technical Sets in 1977,and was renamed Technic in 1984.Technic sets are often characterised by the presence of special pieces, such as gears, axles, and pins. Other special pieces include beams and plates with holes in them, through which the axles could be installed. Some sets also come with pneumatic pieces or electric motors. In recent years, Technic pieces have begun filtering down into other Lego sets as well, including the BIONICLE sets (which were once sold as part of the Technic line), as well as a great many others.