A courtyard with a height that is the same or taller up to three times its width is perceived to be efficient to provide shading in the yard. A courtyard that is too tall may drop its scale and lose its control on lighting and air. A courtyard that is too shallow does not play climatic efficiently because it exposes too much directly under sunshine during hot weather. This theory has been proven by courtyards in the Main Building, whose width/height ratio is greater than 1. The courtyard in Main Building has consequently been recognized as an exemplar of a comfortable sense of space (Lau and Yang, 2009).