Spatial projections (along x,   y and z axis) of the particles in the simulation. The rows show the simulation at z = 0.07, z = 0.1, z = 0.2 and z = 0.3 respectively. We colour code the particles depending on their location: clusters (green/blue), the filamentary region in between (red) and the central part of this filament (cyan). See text for a more detailed definition. Additionally the yellow circles mark the virial radius of the two clusters.