In 1790, there was a Frenchman named Sivrac. He was very mindful. One day, he was walking on a street in Paris, because it had rained the day before and there was a lot of rain on the road, which was very difficult to walk. Suddenly, a four-wheeled carriage rolled from behind. The street was narrow and the carriage was wide. Sifrak hid but was not hit by the car, but was still splashed with mud and rain. When others saw it, they felt sorry for him, and they were so angry that they wanted to call the carriage to stop and make reasonable negotiations. Sifrak murmured, "Don't shout, don't shout, let them go." The carriage went away, and he was still standing on the side of the road. He was thinking: the road is so narrow, there are so many pedestrians, bicycles
Why can't the structure of the carriage be changed? The carriage should be cut in half along the way, and the four wheels become two front and rear wheels... He thought of this, and went home to design. After repeated trials, the first "Trojan Horse Wheel" carriage was built in 1791. This earliest bicycle was made of wood. Its structure was relatively simple. It had neither a driving device nor a steering device. The cyclist relied on his feet to push the ground hard, and could only get off and move the bicycle when changing direction. Even so, when Sifrak rode this bike to the park for a ride, everyone present was quite surprised and admired.