How was the Eight Diagrams Array invented according to tortoise shells in ancient times?

According to legend, in ancient times, turtles came from Luoshui, and there were images on their tortoise shells. The structure is that it wears nine shoes and one shoe, the left three right seven, the two four shoulders, the six eight feet, the five centers, the five white circles are all positive, and the four black dots are negative. The ancients drew this picture after seeing it, which is the origin of the turtle back waterinfo picture.