As you can see, the identical dynamical system with a different start has settled to a different motion. The amplitude of the displacement is larger. The waveform rather than sinusoidal looks more sawtooth. Apparently the Duffing oscillator has two coexisting attractors of period 1. Which one the system settles to depends on the initial position and velocity. This is a complication which we did not see in our previous examination of attractors. The driven pendulum, once the parameters were set, always settled to the same motion.
The Phase Space Projection view projection of this attractor even more clearly than the Position/Velocity vs Time view demonstrates the difference between this and the previous attractor. The scale of the orbit on the screen is held fixed to allow the contrast between attractors to show clearly. In the Phase Space Orbit view we have again shown the different nature of this attractor than the first. This attractor is also a limit cycle but it is severely distorted relative to the sine like orbit in the period 1a case.