Contemporary architectural interpretations of the relations between objects and space have often been cast in the language of gestalt psychology, specifically through the terms figure and ground. (esp. Colin Rowe, Robert Slutzky, Fred Koetter) 

Gestalt psychologists employed the concept of figure and ground to study human pattern recognition, in which a figure (note the anthropomorphic aspects) or universal can be distinguished by its emergence from a (back)ground. One of the classic studies involves dual and contradicting readings such as the duck/rabbit or the two faces/vase. The same aspects of the images are interpreted differently as the guiding gestalt changes. 

These ambiguities have been explored in both aesthetic and philosophical contexts. Wittgenstein and others have described the interpretive act of "seeing as". Rowe and Slutzky outlined an aesthetics of ambiguity described as "phenomenal transparency" .

The condition of figure is also referred to as focal. The condition of ground as field.

in relation to aesthetic space 
Revisionist Urban theory 

see also ground / foundation