What is the configuration of vertical planes that completely encloses a space?

The configuration that completely encloses a space requires a minimum of four vertical planes. This is because such a setup typically defines a three-dimensional space, such as a room or a defined area. The four vertical planes can form the perimeter boundaries—think of a simple rectangular or square room where walls act as the vertical planes enclosing the interior space.

In architectural terms, these vertical planes establish the walls of the environment, ensuring that the space is both functional and usable. While a single vertical plane or two vertical planes may exist, they do not suffice in creating a fully enclosed area. Similarly, while five vertical planes could theoretically enclose a space, it suggests unnecessary complexity without adding practical advantage, except in specific designs or geometries. Thus, four vertical planes strike the necessary balance in typical architectural contexts for complete enclosure.