The Eight Diagrams in the Book of Changes
are actually graphics
. Popularized in the process of development, they were converted into pictures or picture language, called Rail Leather Art.
In the early years of the Northern Song Dynasty, a professional in Shu Guo(the present Sichuan Province) perfected it into the Hexagrams Shadow
. According to recorded literature, it prospered in the Song Dynasty and worked well. However, they were easily seen through or the forecasts were most often wise-after-the events. Thus they gradually went out of sight. Yet its rise and fall was a maverick.