Duffing Oscillator Poincaré Map for various γ parametres with δ=, ω=1, α=-1, and β= 1.

Duffing Oscillator Poincaré Map for various γ parametres with δ=, ω=1, α=-1, and β= 1, with initial conditions, y1, y2 = 1.5, t= 0.