Fig. 3.

Domains used for the test problems presented in this section. Stimulus locations are indicated by the coloured overlay. A: Example of diffuse domains generated using a uniform random distribution for the isotropic and anisotropic test problems. The stimulus for the isotropic problem is indicated by the lighter purple region, and the stimulus for the anisotropic problem is indicated by the darker purple region. B: Tunnel domain used for the third test problem. (For interpretation of the colours in the figure(s), the reader is referred to the web version of this article.)