The design of a sunken courtyard in a courtyard refers to an architectural feature where a lower level is incorporated into the overall layout of a garden or courtyard space. This type of design can create a sense of depth and privacy, often used in traditional Chinese gardens. The layout includes a lower level that is accessed via steps or a bridge, and it can be used for various purposes such as a garden, a pond, or a seating area. The design considerations involve the integration of the sunken area with the surrounding landscape, ensuring harmony and functionality.