emergent behaviour

Behaviour that's amazingly complex, intracate and overall astounding is emergent from a set of simple base rules. (wiki)

Things with emergent behaviour:

Atoms, tiny and simple (relatively), create our universe of infinite depth.

Letters and the alphabet, twenty six of them (plus capitals and some punctuation), can communicate innumerable emotions, thoughts, creations, and experience.

Turing Machines, with their tiny set of actions, can do anything computable. (Same with Conway's Game of Life

Stephen Wolfram seems to believe that cellular automata are the fundamental unifying theory in physics. That's how incredible their emergent behaviour is.