Riddled basins of coupled elastic arches

Riddled basins are shown to occur in a simple mechanical device consisting of masses and springs. Convergence probabilities versus deviations in the i nitial conditions are quantified by three independent methods, all leading to scale-invariance over many decades. Conditions exist for the occurrence of two-state on-off intermittency involving switching between predictable a nd unpredictable oscillations. (C) 1999 Elsevier Science B.V. All rights re served.