tall puppets dressed in silk and playing mouth organs, all powered by pulling ropes and blowing into tubes. As written in the Records of the Three Kingdoms, the engineer Ma Jun (fl. 220–265)—already associated with the differential gear system of the south-pointing chariot—invented a mechanical theater powered by a rotating wooden waterwheel for the entertainment of Emperor Ming's (r. 226–239 AD) court. With the waterwheel in motion, a number of mechanical puppets performed tricks, such as singing girls who played music and danced, other puppets who would beat drums and sound flutes when one puppet entered the scene, puppets dancing on balls, throwing swords, hanging upside down on rope ladders, etc. Other mechanical puppets dressed as government officials did tasks in their offices, puppets dressed as laborers did jobs of pounding and grinding (trip hammer and millstone), while others watched cockfighting, all moving simultaneously. Water-powered puppet theaters in the tradition of Ma Jun were created in later dynasties as well. R Raised-relief map: The raised-relief map may have existed in China since the 3rd century BC, if the accounts in the Records of the Grand Historian (by Sima Qian, 91 BC) about Qin Shi Huang's (r. 221–210 BC) tomb prove correct (if it is excavated). It is known that Ma Yuan (14 BC – 49 AD) created a raised-relief map in 32 AD made out of rice, a type of map described in detail during the Tang Dynasty (618–907) by Jiang Fang in his Essay on the Art of Constructing Mountains with Rice (c. 845). Xie Zhuang (421–466) of the Liu Song Dynasty (420–479) created a 0.93 m2 (10 ft2) wooden raised-relief map of the empire (showing mountains and rivers) which could be taken apart and pieced together like a giant jigsaw puzzle. The Song dynasty polymath Shen Kuo also created his own raised-relief map using sawdust, wood, beeswax, and wheat paste. Restaurant menu: During the early Song Dynasty (960–1279), expanding trade and commerce brought money and people to the Song Chinese capital. The world's first restaurants sprang up and food like dumplings and noodles became available to the masses for a small price. Urban shopkeepers of the merchant middle class often had little time to eat at home, so they ventured out to eat at a variety of establishments such as temples, taverns, tea houses, food stalls, and restaurants which provided business for nearby brothels, singing-girl houses, and drama