Architecture during the Song period reached new heights of sophistication. Authors such as Yu Hao and Shen Kuo wrote books outlining the field of architectural layouts, craftsmanship, and structural engineering in the 10th and 11th centuries, respectively. Shen Kuo preserved the written dialogues of Yu Hao when describing technical issues such as slanting struts built into pagoda towers for diagonal wind bracing. Shen Kuo also preserved Yu's specified dimensions and units of measurement for various building types. The architect Li Jie (1065–1110), who published the "Yingzao Fashi" ('Treatise on Architectural Methods') in 1103, greatly expanded upon the works of Yu Hao and compiled the standard building codes used by the central government agencies and by craftsmen throughout the empire. He addressed the standard methods of construction, design, and applications of moats and fortifications, stonework, greater woodwork, lesser woodwork, wood-carving, turning and drilling, sawing, bamboo work, tiling, wall building, painting and decoration, brickwork, glazed tile making, and provided proportions for mortar formulas in masonry. In his book, Li provided detailed and vivid illustrations of architectural components and cross-sections of buildings. These illustrations displayed various applications of corbel brackets, cantilever arms, mortise and tenon work of tie beams and cross beams, and diagrams showing the various building types of halls in graded sizes. He also outlined the standard units of measurement and standard dimensional measurements of all building components described and illustrated in his book.