Double-decker sunken courtyard floor plan

Quick answer：

A double-decker sunken courtyard is a landscape architectural design feature where a courtyard is situated below ground level, with one level above ground and another level partially or entirely below ground. The floor plan would show the layout and dimensions of the space, including the positions of walls, floors, and any other features such as stairs or landings connecting the levels. This design is often used to create private, sheltered outdoor spaces within a building or urban environment.