In their physical form, cities embody humans’ collective minds, in that they are shaped by humans’ sensory-motor mechanisms. On aggregate, human actions plot invariant patterns that characterize urban structures. In search for natural processes that mark these structures, we outline cross-cultural invariants that cities share in their growth patterns. These invariants are particularly visible in the way cities imitate natural growth in response to large-scale human interventions. Positive feedback mechanisms are enforced by means of preferential attachment where there is an increase in accessibility. Reinforcing feedback mechanisms appear in the form of pruning of weak local structures. On the global scale, steady state monocentric patterns are conserved matching reaction-diffusion in biological systems. The observations yield that cities have inherent natural processes that build their complexity from the micro scale to the macro scale. These observations are part of an on-going PhD research by Kinda Al_Sayed at UCL, BSGS Space Group
