Yingzao Fashi 1 - Drawing. Public domain image.

A diagram of three corbel bracket assemblies in an illustration of a cross-section of a Chinese hall. This is an original picture from the Yingzao Fashi standard building manual published by the Chinese official and architect Li Jie in the year 1103, during the Song Dynasty. The curving profile of purlines and the consequent curve of the roof line is well seen. Lever arms are also present.

This picture appears on page 96 of Joseph Needham's book Science and Civilization in China: Volume 4, Part 3, Civil Engineering and Nautics.