This paper outlines a symbolic computational theory for recognizing variable spatial environments-The Theory of Cognitive Prism, (Dong 2005). This theory defines distance and orientation relations between extended objects using the connectedness relation. The metaphor of cognitive prism is proposed to understand the representation of a snapshot view of an environment such that a cognitive system neglects part of the objects in a snapshot view and subjectively re-arranges selected objects, just like an optical prism which reflects some of the incoming light, re-arranges the incoming part, and forms a spectrum. The recognizing process is interpreted as a judgement of the compatibility between two representations that decides to which qualitative degree they belong to the same environment.