What is the origin of Mingyuan architecture in Gong Yuan?

The Round Building is the central building of Gongyuan in Jiangnan. According to Gong Yuan's inscription, this building was built in the 13th year of Jiajing in Ming Dynasty (1534). Although it has a history of more than 460 years, it is still well preserved. It is the oldest examination building in China. The word "bright future" is taken from the meaning of "be cautious in pursuing the future and be wise in preserving our health" in "University". This building is three stories high, with doors on the ground floor and windows on two floors upstairs. Standing upstairs, you can see Gongyuan, which was playing the role of giving orders and directing the whole examination room. Due to the particularity of location and function, the buildings in Gong Yuan, including those in a certain range outside Gong Yuan, are not allowed to exceed the height of Mingyuan Building. Qingyun Tower, one of the three ancient buildings of Confucius Temple, is located in the People's Playground of Confucius Temple. It was rebuilt in the fifty-eighth year of Kangxi and the twelfth year of Yongzheng, so it has three floors (three floors), adjacent to Gong Yuan, so it was changed to double floors (two floors). In Mingyuan Building, there is a pair of couplets inscribed by Li Yu (Li Daiweng), a famous poet in Kangxi period: "If you engrave harsh words, you will be tired if you watch the gentry crawl around;" I like the people here in the same month, and I can see it at a glance. " During the exam, prison guards, inspectors and other officials went upstairs to monitor, "waving flags during the day and raising lights for help at night." Prevent candidates from making trouble and cheating. Three days before the test, as usual, monks and Taoists set up an altar on the upper floor of Mingyuan for three days and nights to pray for the upper bound and the underworld, and set up a "flag sacrifice" to make soldiers wave flags day and night and shout "Be kind and take revenge." Its purpose is to warn candidates to do good and forbid evil on weekdays, otherwise they will gain something in the examination room. In addition, during the Mid-Autumn Festival, prison guards, supervisors, inspectors and other officials can also go upstairs to enjoy the moon, drink tea, sing songs and look out the window at the famous Qinhuai River lantern.