Mock cluster lensing mass distribution 2. The black circles represent the lenses (cluster members), the grey circles the foreground galaxy (darker grey) and the background galaxy (lighter grey). The cyan triangles, magenta squares and red stars represent the images of the three sources, respectively at z_s1 = 1.5, z_s2 = 2.0, z_s3 = 2.5. The circles radii are proportional to the galaxy’s luminosity relative to the BCG (biggest circle). One far-in-projection foreground galaxy, shown in blue in the right panel, was added to this system (100^″ away from the BCG).