Fu Xi
Chinese origin myths have stories about two primordial sage-rulers being divinely inspired by patterns on turtle shells. Fu Xi devised the "bagua" "eight trigrams" of the "Yijing" from seeing the "Hotu" "Yellow River Map" on a turtle (or a dragon-horse), and Yu devised the basic magic square from seeing the "Luoshu" "Luo River writing" on a giant turtle shell. "The Great Treatise" commentary to the "Yijing" has an early reference to the "Luoshu".