The simplest possible "mechanical cell" would be a self-contained machine that can reproduce itself given only raw materials and energy. This could theoreticall

The simplest possible "mechanical cell" would be a self-contained machine that can reproduce itself given only raw materials and energy. This could theoretically take place on the molecular scale; see http://en.wikipedia.org/wiki/Grey_goo http://en.wikipedia.org/wiki/Grey_goo.