Clockwork refers to the inner workings of either a mechanical clock (where it is also called a movement) or another device that operates in a similar fashion (such as a dial indicator). Specifically, the term refers to mechanisms utilizing a complex series of gears. One of the earliest known examples of a clockwork mechanism is the Antikythera mechanism, a first-century BC geared astrolabe device for calculating star positions, recovered from a Greek shipwreck.A clockwork motor is a clockwork device mechanically powered by a mainspring, a spiral torsion spring of metal ribbon. Energy is stored in the mainspring manually by winding it up, turning a key attached to a ratchet which twists the mainspring tighter. Then the force of the mainspring turns the clockwork's gears, until the stored energy is used up. The adjective wind-up refers to mainspring-powered clockwork devices, which include clocks and watches, kitchen timers, music boxes, and wind-up toys.