Universal constructor

A Universal Constructor is a machine which within some physical or abstract environment is able to construct all environmentally possible constructions. The notion originated with John von Neumann, providing part of his solution to the problem of self-replication. It now has wide application to emerging technologies and uses. [ref: NASA, etc.]

Examples of such machines do not exist, except as mathematical abstractions.

In 1968, Edgar F. Codd devised an 8-state 5-neighbor cellular automaton that he showed to be a universal computer-constructor. Five years later, in 1973, John Devore modified Codd's work and reduced the size of the self-reproducing machine.