This paper identifies fundamental processes behind urban design in which rules are derived from connective principles in complexity theory, pattern recognition and artificial intelligence. An urban setting can be decomposed into human activity nodes and their interconnections. The connections are then treated as a mathematical problem (here in a qualitative manner). Urban design is most successful when it establishes a certain number of connections between activity nodes. The creation of the built environment is driven by forces analogous to those that lead us to do mathematics.