What's the number of turtle shell?

I guess the answer is "wearing nine shoes and one shoe, three on the left, seven on the right, two on four shoulders, and six on eight is enough" 294 357 6 18, which is an allusion related to tortoise shells. It is said that the Yellow Emperor or someone (forgive me for being illiterate here) saw a turtle one day. The patterns on the turtle's back were arranged in nine grids, each with dots, as I listed above. Then he deduced a lot from this, and later generations continued to deduce the Yijing, gossip and so on.

Satisfied, please adopt.