development is genetically driven, he makes no attempt to explain how this works and even offers evidence to the contrary. He observes, for instance, that genes ordinarily determine peripheral traits, such as eye color, rather than "focal" traits, such as the structure of the eye itself. Moreover, when genetic mutation influences basic structures, the result tends to be the complete transformation of a structure into another rather than piecemeal change, which Waddington illustrates with the developmental ball rolling out of one creode into another. Thus his account gives the impression that genes influence development, perhaps altering the course of a region of cells, without determining the endpoints toward which the embryo develops. This interpretation is further reinforced by Waddington's discussion of the organization of the gene pool, where he points out that "the epigenetic process occurring during the development of the organism might be so buffered or canalized that the optimum end-result is produced irrespective of the genes which the individual contains." The more deeply creodes are carved into the epigenetic landscape, the weaker the influence of genes over development. He also argues that deep creodes will resist not only genetic but environmental pressures to change course. This phenomenon, which he calls "stabilizing selection," puts genes and environment on a par in secondary importance compared to the epigenetic system. Waddington's emphasis on epigenetics over genes prefigured the current interest in evolutionary developmental biology. As Sean B. Carroll and others have explained, genes involved in development are roughly the same in all animal species, from insect to primate. Instead of mutations in developmental genes, evolution has been driven by changes in gene expression, namely which genes are expressed at which times and locations in the developing organism. Architecture Architectural theorist Sanford Kwinter described the concept of the chreod as "the most important concept of the 20th century." The word "chreod" also closely describes paths of decision within what Christopher Alexander has called configuration space, his term for what he notes that Stuart Kaufmann calls "fitness landscape." By Alexander's theory, because conscious human design decisions do not need to follow these chreods, conscious human design can lead to mixed results. Therefore, he proposes that discovering ways to allow architecture to follow these paths is the best way to get good results in the built environment. Alexander sees his theories of "The Fundamental Process", "structure preserving transformations" and "15 fundamental properties" which he