The Song artist Zhang Zeduan 's painting Along the River During the Qingming Festival depict the Dongshui Gate in detail : the building on top had a five @-@ ridged roof with a shallow slope in the Song dynasty style , supported prominently by two sets of brackets ( dougong ) . The lower bracket assembly rested on the city gate to form a wooden foundation , while the upper assembly supported the roof , similar to the dougong in an extant Song building , the Goddess Temple in Taiyuan . This method of using bracket assemblies to support superstructure was specified in Li Jie 's 12th @-@ century building manual Yingzao Fashi as pingzuo ( literally " flat base " ) .