When the core is massive enough, it can efficiently accrete particles with τ_f = 1 entering its Hill sphere (indicated by the white circle in the first panel). On this scale, the Keplerian shear dominates over the relative velocity difference between the gas and Keplerian velocity (Δ = 0.05). Accretion seems to occur through a particle disc, visible after a steady state has set in (panel 2 to 3). In the last panel, accretion and Keplerian shear have removed most particles in the box. The colour coding is similar to Fig. 5. The simulation was performed in a stratified shearing sheet box with Z = H_p/H = 0.01.