 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).Shen Kuo (1031-1095) created a raised-relief map using sawdust, wood, beeswax, and wheat paste.