 The Song artist Zhang <unk> 's painting Along the River During the <unk> Festival depicts the <unk> Gate in detail : the building on top had a five @-@ <unk> 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 <unk> ( literally " flat base " ) . 
