78 year old retired art editor Yan Xinqiang and 45 year old Chinese language teacher Yan Gongming are a father son duo from the Great Wall. Since 1984, the father and son have been self funded to jointly inspect, film, and record the Great Wall of different eras and types in various regions. In 1996, the father and son found the filming location of revolutionary photographer Sha Fei's work "Battle on the Ancient Great Wall" in Futuyu, Laiyuan County, Hebei Province, based on clues such as the shape of the Great Wall and the silhouette of the mountain shadows. Based on their previous research experience, the two gradually shifted their focus on studying the form of the Great Wall. After collection and sorting, Yan and his son classified the forms of the Great Wall and compiled it into a book called "Atlas of the Forms of the Great Wall", which was published in 2023. The endless Great Wall has been dissected into various parts such as walls, doors, piers, platforms, buildings, pile holes, stone carvings and brick carvings, and further subdivided into different forms. Yan's father and son hope that their efforts can help more people understand the details of the construction of the Great Wall, and also provide reference for the protection and restoration of the Great Wall. The nearly 40 years of joint inspection of the Great Wall have made it a common emotional bond between father and son. At present, the two are still conducting specialized research on the shape of the Great Wall. (Lai Xin She)