  Sustainable urban design or planning is not a LEGO-like assembly of
prefabricated elements, but an embryo-like growth with persistent
differentiation and adaptation towards a coherent whole. The coherent whole has
a striking character - called living structure - that consists of far more
small substructures than large ones. To detect the living structure, natural
streets or axial lines have been previously adopted to be topologically
represent an urban environment as a coherent whole. This paper develops a new
approach to detecting the underlying living structure of urban environments.
The approach takes an urban environment as a whole and recursively decomposes
it into meaningful subwholes at different levels of hierarchy or scale ranging
from the largest to the smallest. We compared the new approach to natural
street and axial line approaches and demonstrated, through four case studies,
that the new approach is better and more powerful. Based on the study, we
further discuss how the new approach can be used not only for understanding,
but also for effectively designing or planning the living structure of an urban
environment to be more living or more livable. Keywords: Urban design or
planning, structural beauty, space syntax, natural streets, life, wholeness
