We can interpret this organising group of fans as a central control that decides what colour should be handed out to the individual spectator. Without this central control, the choreographic scenery would fail. There is no central control to tell the individual spectator to do a specific thing at a given time, rather it is an emergent behaviour. Impressive choreographic scenery made by Lazio s tifosi in Curva Nord of the Olympic Stadium in Rome. The scenery is constructed when each spectator holds up a coloured piece of paper.
Emergent behaviour is an interesting phenomenon that can be observed in natural systems.
We define emergent behaviour as being the behaviour of a system that is the product of interaction between smaller sub-systems. The emergent behaviour is of higher complexity than the sum of the behaviours of the smaller sub-systems. The reason that behaviour of higher complexity than the sum can emerge is the interaction between the sub-systems. Emergent behaviour is known from flocks of birds, schools of fish and herds of land animals. When observing a flock of birds, we will notice that there is no apparent leader in the flock and there appears to be no central control of motion.