Cattle herding Liu Ma was a means of transportation invented by Zhuge Liang, prime minister of Shu and Han Dynasties in the Three Kingdoms period, which was divided into cattle herding and Liu Ma. It was used by Zhuge Liang in the Northern Expedition from the 9th to 12th year of Jianxing (23 1-234). Its carrying capacity is "one-year-old grain", about 400 kilograms, and its daily journey is "dozens of treks, three miles in groups", providing food for 100 thousand troops in Shu and Han dynasties. But the specific way and appearance are unknown now, and there are different explanations.
The expression of wooden cows and flowing horses in the Three Kingdoms is just as you said. It can run unconditionally without energy. This is a perpetual motion machine. The meaning of perpetual motion machine is as follows:
Perpetual machine is a kind of so-called machine that can continuously move and do work without external input energy or only one heat source. Machines that can do work forever without consuming energy violate the law of conservation of energy, so they are called "perpetual motion machines of the first kind".
Extended data:
The idea of perpetual motion machine originated in India. Around the year 1200, this idea spread from India to the Islamic world, and from here to the west. In Europe, one of the most famous perpetual motion machine designs in the early days was put forward by a Frenchman named Hennecau in the13rd century. As shown in the figure: there is a rotating shaft in the center of the wheel, and 12 movable short rods are installed at the edge of the wheel, and one end of each short rod is equipped with an iron ball.
The designer of the scheme thinks that the ball on the right is farther from the axis than the ball on the left, so the rotating torque generated by the ball on the right is greater than that generated by the ball on the left. In this way, the wheel will rotate endlessly in the direction indicated by the arrow, driving the machine to rotate. This design has been copied by many people in different forms, but it has never been endlessly turned over.
After careful analysis, it will be found that although the torque produced by each ball on the right is large and the number of balls is small, the torque produced by each ball on the left is small, but the number of balls is large. Therefore, the wheel will not continue to rotate to do work, but will only swing a few times and stop.
References:
Baidu encyclopedia-perpetual motion machine