Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany. demian@nld.ds.mpg.de|Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany. demian@nld.ds.mpg.de|Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany. demian@nld.ds.mpg.de|Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany. demian@nld.ds.mpg.de