Fig. S3.

Spiral wave initiation due to a FPR in a 2D medium. Within the domain with a dense filling, $D=D_0=0.001$ cm²/ms. Within the domain with rare filling, $D=D_0/5$. Within the rest of the medium, $D=D_0/20$. Snapshots of an initially right-traveling wave are shown. (A–F) The trajectory of the created phase-change point is shown by a white line. The domain has a size $3\times 3$ cm², The FPR radius is $0.5$ cm, and the parameter ${\tau }_d=0.40$.