What are the four words on the tablet of Langzhong Gong Yuan?

Langzhong Gong Yuan, also known as Gong Yuan in northern Sichuan and Gong Yuan in Sichuan, is located in the ancient city of Langzhong, Sichuan Province.

Hiram Hospital, also known as "experimental shed". It is the examination room for literati in the imperial examination era. Langzhong Gong Yuan is located in Xuedao Street, Langzhong City, Sichuan Province. According to "Langzhong County Records", "In the ninth year of Shunzhi, Renchen (1652), the whole Sichuan was not peaceful, so Xin Maoke made up for the provincial examination and surrounded Baoning House. Ding You and Geng Zi were all in Baoning, and returned to the capital in the second year of Kangxi (1663). In the twenty-second year of Jiaqing, Li led the reconstruction of Chuanbei Road.

There is no exact record about when the Gong Yuan experimental shed was built. According to Jiajing's "Baoning Mansion Records" in Ming Dynasty, there is a building complex called Minglun Hall with 40 examination rooms.

The four words above are "Langzhong Gong Yuan".