Four-door introduction: The obvious difference between the barracks and the southeastern folk houses is its front door. The front door facing the street is divided into two specifications: four doors and six doors. Four doors are for ordinary people's homes, while six doors are for officials' homes. The so-called four doors mean single doors on the left and right, and a double door in the middle. If someone in a family gets promoted, they can "change the door" and change the single doors on both sides to double doors, making it six doors.