About the cover: "Reconfigurable machines"

The basic notion behind the cover of this issue was Paulien Hogeweg's growing polyautomata, used as a metaphor for reconfigurable machines. Hogeweg's work (1974), reflecting one of the current important efforts to marry computer sciences with biology, uses automata theory to explain the growth behavior of living things. The "genes" (4-ary strings) for the filamentary organisms like those shown on the cover are produced by a very simple set of eight rules. The phenotypic expression of the genesi. e., the actual physical expression of the simulated genetic code-can be amazingly lifelike, as evidenced by the pictures below and on the facing page, which represent steps in the creation of the final image on the cover.