Fig 11 -

The panels show the evolution of order parameter of the upper layer with the increase of intra-layer coupling strength for different network topologies, (a) both the upper and lower layers are random networks, (b) both the upper and lower layers are scale-free networks. The inter-layer coupling strength λ is set to 0.9. The natural frequency of each oscillator in the upper layer is randomly selected in the interval [-1, 1], and the natural frequency of oscillators with the same label in the lower layer changes synchronously. Because the upper and lower networks belong to the same type, the evolution of order parameters is almost the same. In order to avoid repetition, the evolution law of order parameter of the lower layer is omitted.