Emergent structures are patterns not created by a single event or rule. Nothing commands the system to form a pattern. Instead, the interaction of each part with its immediate surroundings causes a complex chain of processes leading to some order. One might conclude that emergent structures are more than the sum of their parts because the emergent order will not arise if the various parts are simply coexisting; the interaction of these parts is central.
- Ripple patterns in a sand dune created by wind or water is an example of an emergent structure in nature.
- A termite "cathedral" mound produced by a termite colony: a classic example of emergence in nature.
The World Wide Web (WWW) is a popular example of a decentralized system exhibiting emergent properties.