The wooden piece already featured one fixed and a movable jaw.[12][13] Truss roof 550 BC[14] See List of Greco-Roman roofs Crane c. 515 BC Labor-saving device that allowed the employment of small and efficient work teams on construction sites. Later winches were added for heavy weights.[15] Escapement 3rd century BC Described by the Greek engineer Philo of Byzantium (3rd century BC) in his technical treatise Pneumatics (chapter 31) as part of a washstand automaton for guests washing their hands.