I Ching

http://www2.unipr.it/~deyoung/I_Ching_Wilhelm_Translation.html

• 6 (3 tails) is considered a changing yin and is drawn as a broken line with an X in the middle. 9 (3 heads) is considered a changing yang and is drawn as a solid line with a circle in the middle.
• 7 (2 tails, 1 head) is considered an unchanging yang, and is drawn as a solid line. 8 (2 heads, 1 tail) is considered an unchanging yin and is drawn as a broken line.

https://www.ichingonline.net/instruction.php

http://jamesdekorne.com/GBCh/ichingdl.htm