to light another fire. They were pinewood sticks impregnated with sulfur and needed only a slight touch from a flame to light. This was written in the Records of the Unworldly and Strange by Tao Gu in 950 (Five Dynasties and Ten Kingdoms period). Mechanical theater (driven by carriage wheels): The inventors of the field mill mentioned above, Xie Fei and Wei Mengbian of the Later Zhao (319–351 AD), also invented an intricate mechanical theater mounted on a carriage, its figures operated by motive power (i.e. simply advancing the carriage forward). From 335 to 345 AD, they worked at the court of the ethnic-Jie emperor Shi Hu (334–349). The vehicle they crafted was a four-wheeled and 6 m (20 ft) long carriage that was about 3 m (10 ft) wide. On it rested a large golden Buddha statue with a Daoist statue continually rubbing his front with his mechanical hand. The Buddha was also surrounded by ten wooden Daoists who rotated around him in a circuit, periodically bowing to him, saluting him, and throwing incense into a censer. Above the Buddha were nine dragon-headed faucets which spouted water. Like the field mill and the pounding cart of these two inventors, when the carriage halted, so did all of its moving components of mechanical statues and spouting faucets. Mechanical cup-bearers and wine-pourers on automatic-traveling boats: The mechanical engineer Huang Gun served the court of Emperor Yang Di (r. 604–617) and wrote the book Shuishi Tujing on his inventions, which his colleague Du Bao enlarged and commented on. He constructed seven small boats, called 'wine boats', that were as large as 3 m (10 ft) long and 1.8 m (6 ft) wide which supported a number of mechanical figures of wooden statues called 'hydraulic elegances', each about 0.6 m (2 ft) tall, some of them animals but most in human form consisting of singing girls, musicians playing actual instruments, dancers and tumblers, oarsmen busy rowing, cup-bearers, and wine-pourers all moving simultaneously as if alive. These boats were set to travel at timed intervals along circuits made of winding stone channels and canals in palace courtyards and gardens (designed by Tang Haogui), where guests would gather for special occasions. The cup-bearer stood at the bow of each ship and beside him the wine-pourer; when the ship made automatically timed periodic stops where guests were seated, the cup-bearer automatically stretched out his arm with