From left to right: cluster luminosities (in 10¹⁰   h^-2   L_⊙) vs. their environmental densities at the smoothing lengths 4, 8, and 16 h^-1 Mpc (in units of mean density) (grey circles). The size of circles is proportional to the number of components found by 3D normal mixture modelling. Stars denote most multimodal clusters, and filled circles denote most unimodal clusters as described in the text.