A Beijing Quadrangle Courtyard (Siheyuan), is a traditional Chinese architectural style consisting of a rectangular courtyard surrounded by single-story buildings on all four sides. Its layout typically includes a main house (north), side houses (east and west), and an opposite house (south), forming a private, enclosed space. The design reflects ancient Chinese principles of harmony, family hierarchy, and Feng Shui.

The main house was reserved for the family elders, while the side houses were for younger generations or guests. The courtyard served as a communal space for family activities and natural light. Siheyuans are a symbol of traditional Chinese culture and are often associated with Beijing's historical neighborhoods, such as the hutongs. Today, many have been preserved or restored, offering a glimpse into China's architectural heritage.