Mass density distribution, color coded in M_⊙ kpc⁻², of the central region of the Cluster-2, and Cluster-3 mocks. As in Fig. 1, green circles denote the galaxies for which we have a measured velocity dispersion, while cyan crosses are the observed multiple images. The same set of measured and unmeasured galaxies selected in Fig. 1 are labeled in green and blue, respectively. Right panel: magenta data points are plotted showing the spatial distribution of the low-mass subhalo population of Cluster-3.