Fractional radius amplitude for the second overtone (A₂) and for the first overtone mode (A₁), for nine consecutive models located along evolutionary track of 2.5M_⊙ (Z = 0.006). The models were initialized with a range of amplitude ratios. The effective temperatures of the models and linear P₅/P₁ period ratios are given in each panel. The approximate location of the attractors is marked with filled circles. For the models with a double-periodic attractor the periods P₁ and period ratios, P₂/P₁, are also given. All trajectories in the first five panels evolve towards a single-periodic second overtone attractor. In the next three panels (panels 6–8) a double-periodic attractor is clearly visible. In the last panel, all trajectories evolve towards a single-periodic first overtone attractor.