On the one hand, Alexander expands the repertoire of design to include activity. But on the other, he quickly codifies and taxonomizes that activity. He mimics the object of this own critique by reforming the artificial with a “natural” corrective—instead of the tree, the semi-lattice becomes the placeholder. Despite his attempt to incorporate active form and information, Alexander only creates another immobilized form.

In his 1965 article “The City is not a Tree,” he critiqued what he deemed to be the infrastructural or organizational template of many settlements and cities. A “tree,” in Alexander’s parlance, is a branching structure in which sets are either completely disconnected from one another or entirely contained within one set without overlapping sets. The branches do not grow together but emanate separately from a single trunk.