  A nonlinearly coupled system of bouncing balls is shown to exhibit features
like self-organised-criticality (SOC) and punctuated equilibrium (PE) in
suitable parameter domains. The temporal evolution of the non-stationary
amplitudes is analysed through local methods to unravel the transient periodic
components and fluctuations giving rise to SOC and PE type behaviours. This
simple dynamical system follows Gutenberg-Richter relation and also manifests
the Devil's staircase, explicating the universality of these features in
diverse complex systems.
