First of all, Mu Niu Liu Ma is an ordinary unicycle.
According to the Records of History of Song Dynasty, Mountain on the Altar and Biography, wooden carts in Han Dynasty were called deer carts, which were improved by Zhuge Liang and called wooden oxen flowing horses. During the Northern Song Dynasty, the name of unicycle began to appear in Shen Kuo's Meng Qian Bi Tan. The shape and structure of this kind of unicycle are slightly different due to local conditions, so it is called trolley, second-hand man and second-hand man everywhere.
Second, Liu Ma is a four-wheeled vehicle.
Gao Cheng's "Tale of Tales" said in Volume 8: (Zhuge Liang first made it) Mu Niu, that is, this car has a front axle; Zhuge Jiliang and Zi Tongzhi Bamboo Slips all have evidence, and Fan Wenlan clearly put forward this view. The irrefutable evidence is that a portrait brick of a parallel car unearthed from the No.2 Han Tomb in Yang Zishan, Chengdu, has the image of a wheelbarrow pushed by someone in the lower right corner, hence the name "wooden ox flowing horse", because wheelbarrows don't need cattle and horses, just as people call tractors iron oxen today.
3. Muniu is an automatic machine composed of connecting rods, gears and other mechanisms.
This theory is represented by Biography of Zu Chongzhi in Nanqi, Guang Ji of Taiping and Ci Yuan. Its main contents are as follows: During the Three Kingdoms period, it was not uncommon to use the gear principle to manufacture machinery. In the Eastern Han Dynasty, Bilan rollover was an instrument that used gears to rotate to draw water. During the Three Kingdoms period, South Korea and Japan also made water rafts, which were irrigated by water wheels driven by water.
Biography of Zu Chongzhi in the Southern History: Zhuge Liang is a horse, but he made a device, not because of Feng Shui, but because of luck, and he didn't work hard. We can see that Zu Chongzhi once saw Mu Niu Liu Ma with his own eyes, and because of its inspiration, he created a tool for mechanical operation, which is better than Mu Niu Liu Ma. Therefore, Mu Niu Liu Ma must be made by the gear principle, otherwise Zu Chongzhi would not be interested in using it as a reference.