Upper panel: Full projected data from both simulations from R22. Each square has a side length of 8h⁻¹Mpc, and corresponds to a 80h⁻¹ Mpc projection depth. Panel (b) contains fewer small-scale dark matter halos than panel (a) as the free-streaming length is longer in 1 keV than in 3 keV WDM. Lower panel: Non-Halo projected data from both simulations from R22. Each square has a side length of 8h⁻¹Mpc¹, and corresponds to a 80h⁻¹Mpc¹ projection. Panel (c) contains smoother and less clumpy structures at small scales than panel (d). The markers are all at the same coordinates and show the regions from which we select the non-halo material used as additional perturbations in our gravitationally lensed systems. These correspond to the highest density of non-halo material in both simulations and to the densest halo in both simulations, excluding those which are cut in the top-left corner.