In the Greek legend of Dido Enclosure, the mutton king of Tyre had a smart and beautiful princess named Dido. Dido lived a happy life in her kingdom, free and carefree, but it didn't last long. Unfortunately, her husband was killed by her brother, the King of Cyprus. Poor Dido fled to the west coast of Africa. She wanted to live here, so she took out her jewels, jade articles and gold coins and planned to buy some land from the local chief Jabbas to build a house. Dido said to the chief, "I just need a place where cowhide is wrapped." The chief didn't think about how big a piece of leather bag could be, so he picked up a big bargain and readily agreed. Dido asked for a cow, killed it, skinned it, cut the cowhide into long strips and prepared to enclose it with cowhide. Dido thought, if this cowhide strip is circled into a rectangle, the circled place is not big enough, and the circled place is not big enough.

It's better to change it to a circle, so the circle is the largest. Then Dido suddenly thought that the land given to him by the chief was by the sea. If pimps can form a semicircle along the coast, this semicircle of land must be the largest. Clever Didi replaces the land boundary with the natural coastline, which is equivalent to invisibly increasing the length of cowhide strips. So she circled a semicircle with cowhide strips, which was the largest area she could circle. Later, Dido established Carthage there. Today, the monument to Carthage is still preserved. Tian Ji, the general of horse racing in Tian Ji, likes horse racing very much. On one occasion, he and Qi Weiwang agreed to compete. They agreed to classify their horses into upper, middle and lower classes. During the race, you should mount the horse against the horse, middle horse against the middle horse, and dismount against the horse. Because horses of all grades in Qi Weiwang are much better than those in Tian Ji, Tian Ji failed in several races. Tian Ji was very disappointed. Before the end of the race, he left the racecourse in frustration. At this moment, Tian Ji looked up, and there was a man in the crowd who turned out to be his good friend Sun Bin. Sun Bin called Tian Ji, patted him on the shoulder and said, "I just watched the horse race. Wang Wei's horse is not much faster than yours. " Before Sun Bin finished, Tian Ji glared at him: "I didn't expect you to dig at me!" Sun Bin said, "I'm not being sarcastic. I mean, if you compete with him again, I can definitely let you beat him. " Tian Ji looked at Sun Bin doubtfully. "You mean the other horse?" Sun Bin shook his head and said, "You don't even have to change a horse." Tian Ji said confidently, "That's different!" Sun Bin said confidently, "Just do it according to my arrangement." Qi Weiwang won many battles, and when he was proudly boasting about his horse, he saw Tian Ji and Sun Bin coming head-on, stood up and said sarcastically, "Why, are you still unconvinced?" Tian Ji said: "Of course not, let's play again!" Say, "Hua", poured a lot of money on the table, as his bet. Qi Weiwang chuckled at this scene, so he ordered his men to bring all the money he had won several times before, add 1200 gold and put it on the table. Qi Weiwang said contemptuously, "Let's start!" Gong sounded and the game began. Sun Bin was a bad horse, lost to Qi Weiwang's good horse, and lost the first game. Qi Weiwang stood up and said, "I didn't expect the famous Mr. Sun Bin to come up with such a clumsy countermeasure." Sun Bin ignored him. Then the second scene. Sun Bin took the first-class horse to compete with the middle-class horse in Qi Weiwang and won a race. Qi Weiwang was a little flustered. In the third game, Sun Bin took China and Malaysia against Qi Weiwang's inferior horse and won another game. This time, Qi Weiwang was dumbfounded. The result of the game was two out of three. Of course, Tian Ji beat Qi Weiwang. The same horse, because it changes the order of appearance in the race, will get the result of turning defeat into victory.