Abstract
This article claims that some familiar properties of phrase structure reflect laws of form. It is shown that optimal sequencing of recursive Merge operations so as to dynamically minimize c-command and containment relations in unlabeled branching forms leads to structural correlates of projection. Thus, a tendency for syntactic structures to pattern according to the X-bar schema (or other shapes exhibiting endocentricity and maximality of ‘non-head daughters’) is plausibly an emergent epiphenomenon of efficient computation. The specifier-head-complement configuration of X-bar theory is shown to be intimately connected to the Fibonacci sequence, suggesting connections with similar mathematical properties in optimal arboration and optimal packing elsewhere in nature.