Every corner of Forbidden City has a turret tower(Jiaolou, 角楼) with nine griders, eighteen columns and 72 ridges. It is marvelously beautiful. How were four turret towers constructed? There is a related story.
Zhu Di, used to be King of Yan Kingdom, became the emperor of Ming Dynasty in Nanjing and wanted to move the capital to Beijing, because Nanjing just the place where he was a prince. Afterwards, he sent one of his dependable officials to Beijing to take charge of constructing Forbidden City. This official was told that he must build four fabulous turret towers at the four corners of outer wall of Forbidden City. Each corner should be decorated with nine beams, 18 columns and 72 ridges. Zhu Di also said to this official: “you act as a supervising minister, and you will be killed if you can not successfully complete this project”. This official was too worried about how to build the beams, columns and ridges.
The supervising minister summoned the workmen and craftsmen of 81 groups after he arrived in Beijing and declared the meaning of Emperor. The time limit was three months for them to build up these four unique turret towers. He stressed: “if they can not be built, the emperor will kill me. But before my death, I will kill all of you, so please be careful of your heads”. The workmen and craftsmen were also unsure about how to build such kind of turret towers, and had to get together to think about the solutions.
The time for completing the construction was very short, only three months. Flashily, one month elapsed. The workmen and craftsmen were still in trouble with how to build these buildings. These men felt anxious except a carpenter who always wandered on the streets.
When he walked on the streets, he heard afar the sounds of crickets, and then he also heard the voice for hawking goods. He walked closely and saw an old man shoulders many crickets cages weaved by straws in different sizes. One of them was weaved like a turret. This cage inspired this carpenter too much. He was exultant and bought this cricket cage, because he thought out the solution. After he came back, he shared his idea with his colleagues that they can build the turret towers modeling this cage, which luckily also was weaved with nine beams, 18 columns and 72 ridges. All of them were quite happy. Finally, the turret towers were successfully built in time.