Example section from a 1-phase clumpy density distribution (spherical clumps of constant density). The 2-phase distributions appear identical albeit with the intraclump space filled with a diffuse medium 10^-4 times less dense than the clumps. This figure is constructed in a similar manner to Figs. 5, 9, but the source is no longer within this section of the model due to the extreme length of the cuboid. In the ISM models, the source is not placed at the centre, but at a point 95% of the length of the model cuboid. This section is that closest to the observer.