The evolution of an ensemble with 10 trajectories after a considerably long time from the different initial condition: (a) f = 0 and , the coexisting attractor case, (b) f = 0.1 and , the single attractor case. (c) Constituent parts of a solution exhibiting negative mobility controlled by the single attractor shown in panel (b), evolving for an external driving period τ. The other parameters are the same as that in Fig. 1.