effect drawing of small apartment sunken courtyard

Quick answer：

A sunken courtyard in small apartments is a design feature where the courtyard is below the level of the apartment. It provides a private outdoor space that can be used for relaxation, gardening, or as an extension of the living area. Effect drawings are detailed illustrations used in architectural design to show the appearance and layout of a space before construction. These drawings can help visualize the design and plan the construction process.