Large map (see text) showing one representation of the test ensemble, consisting of randomly distributed clumps. The colour scale gives the line centre intensity of the 1.9 THz [Cii] transition where the line intensity is highest in the outer layer of each clump. This maps shows the 22nd representation from Fig. A.3. The ensemble is shown in a superpixel, in other words with the area filling factor of a normal 0.01 pc pixel, but scaled in the lateral directions to contain enough clumps of each size.