From the first draft. Some characteristic ideas have been retained, such as: two balls, one ball presses down one end of the lever, so that the other end touches the other ball and starts to move. And the pulley that will be used many times.Since the spinning orbit of the first draft of the second ball was falling in a way that could not be explained by statics, I changed it to a continuous, discontinuous inclined plane. 
     After thinking again, I found it difficult to implement the next part of the first draft, so I deleted it but did not think of a new replacement plan for the time being.After the actual measurement of the site, I changed the positions and distances of some components, and added new components to make the two balls interact more frequently and make the machine more interesting. At the same time, the bottom part of the machine was optimized to ensure that the flags were displayed smoothly. Two new Pulley-like structures were added, allowing the ball to fall into a box on the right, pulling up the block that stopped the car, which then pulled the Flag up through the rope. 
     When designing the model, I initially wanted to make the main track with a hard paper. However, in the process of experiment, I found that the paper was too easy to bend and the probability of failure was very high, so I changed to thin wood to make it, which improved the stability of a lot. There are also problems at the bottom in the section about Flag. The original design in the experiment was too long and too many conversion points, resulting in too much friction, so that the car could not pull up the flag. So I had to shorten the distance and reduce the number of conversion points, so I just pulled the flag out of a small room to show it. After several minor adjustments, the production of the model was finally completed. 

     One ball is placed in the white platform at the upper right, and then put another ball in the upper left. The left ball rolls down, then lift the first lever up, so that the right end of the lever touches the right ball, so that the right ball starts to move.

     The left ball reaches the second lever through two inclined planes and raises it, so that the right end of the lever lifts a small platform connected by the left end of the first Pulley. At this time, the ball on the right passes through the four inclined planes and will roll into this plane at approximately uniform speed. However, due to gravity, this plane will drop at a uniform speed, so that the other plane connected by Pulley's right side will be lifted up and the ball will reach the position reached by the next inclined plane. Because of gravity, the platform will descend again, transporting the ball to the lower level of the inclined plane.

     At this time, after passing the second lever, the ball on the left has gone through three inclined planes in a row and finally reached the car, but the car was blocked by an obstacle and could not move. On the other side, the ball on the right has gone through three inclined planes to the second Pulley. Due to its own gravity, the platform on Pulley's right side will drop to the bottom, thus removing the obstacle blocking the car on the left side. In this way, the left car can start moving on the inclined plane due to gravity. Due to the lines connected to the car and the flag, the flag will be slowly pulled out as the car moves. End of the demonstration.