Ten square sunken courtyard illustration

Quick answer：

A sunken courtyard is a type of garden design where the courtyard is below the level of the surrounding ground. This design can create a more intimate and private space. The 'Ten square sunken courtyard illustration' likely refers to a diagram or visual representation of a sunken courtyard measuring ten square units in size, showcasing its layout, architectural elements, and landscaping. This kind of illustration is often used in landscape architecture and gardening for planning and visualization purposes.