Phase diagrams revealing regions of different wave forms: stable spiral waves (i.e., rigidly rotating spiral waves) (S), meandering spiral waves (M), turbulence 1 (T1, cf. Fig. 7), turbulence 2 (T2, cf. Fig. 8), no wave (N), for m = 1 (a), 2 (b), 3 (c), 4 (d), 5 (e), and 6 (f).