The Han dynasty general Ma Yuan made a raised-relief map of valleys and mountains in a rice-constructed model of 32 CE. Such rice models were expounded on by the Tang dynasty (618–907) author Jiang Fang in his "Essay on the Art of Constructing Mountains with Rice" (c. 845). A raised-relief map made of wood representing all the provinces of the empire and put together like a giant () jigsaw puzzle was invented by Xie Zhuang (421–466) during the Liu Song dynasty (420–479).