Visualisation of 100 2D skeleton realisations (dark blue lines). Also shown are 3D true skeletons (red lines; projection for 3D filaments between ±3R_halo). The same galaxies in the 100 realisations of the 2D slices are blue points and the galaxies that are actually enclosed in ±3R_halo along the line of sight are circled in red. The black circles are centred on the cluster halo, with radius equals R_halo.