Turtle: refers to a triangular pyramid. "Nine Chapters of Arithmetic and Business": "If you solve the cube obliquely, you will get two obstacles. The circuitous tunnels are Ma Yang and Turtle Tunnel. It is not easy for a horse to come second and a turtle to come first. Combine two turtles and three into one, and test it with chess, and its shape is revealed. " Liu Hui's note: "The person who gets this skill, the back joint, or the half-yang horse, looks like a turtle elbow, hence the name Yun. If you beat Ma Yang in the middle, you will get two turtles. The number of turtles is the same, but the certificate is half, so the cloud is six and one. "

On the afternoon of June 7th, 2015, two nouns "biē nào" and "Yang Ma" appeared in a geometry question in the mathematics volume of Hubei liberal arts in the 2065 438+05 college entrance examination. Ancient Chinese characters appeared in the math exam, which quickly spread on the Internet and became a hot topic. Question 20 of liberal arts mathematics involves the knowledge in "Nine Chapters of Arithmetic and Business". First of all, explain what "turtle" and "mother" are, and solve the problem according to these two words and related materials.