In the hatched area we
observe the coexistence of PR (two symmetric pairs of 1 : 1 or 1 : 3 or 1L1R PR) and the steady state of the pendulum. The
largest area with one attractor is a tongue of 2 : 1 resonance. For other resonances (1 : 1, 2 : 3, 2 : 5, 1 : 2) these areas are
small. Especially, it is surprising for 1 : 1 where the resonance tongue is large in the parameter space but only near its edge
we do not find the second attractor.