structural:reformatting, quality:correction
Cellular automata, DNA and the universal constructor

Von Neumann's mathematical analysis of the structure of self-replication preceded the discovery of the structure of DNA. Ulam and von Neumann are also generally credited with creating the field of cellular automata, beginning in the 1940s, as a simplified mathematical model of biological systems.

In lectures in 1948 and 1949, von Neumann proposed a kinematic self-reproducing automaton. By 1952, he was treating the problem more abstractly. He designed an elaborate 2D cellular automaton that would automatically make a copy of its initial configuration of cells. The Von Neumann universal constructor based on the von Neumann cellular automaton was fleshed out in his posthumous Theory of Self Reproducing Automata. The von Neumann neighborhood, in which each cell in a two-dimensional grid has the four orthogonally adjacent grid cells as neighbors, continues to be used for other cellular automata.