Results for the simplified Ormel’s model starting with n₀ = 32 768 representative particles. Top row: ϵ = 0 (no fragmentation); bottom row: ϵ = 0.01 (rubble pile model). Every swarm is represented by a spherical shape with a colour indicating its planar rms eccentricity. The area covered by the shape represents the mass in the swarm. All swarms initially have the same mass, but individual particles can accrete mass held by other swarms and thereby grow beyond their initial swarm size. The vertical lines indicate the critical radius R_crit (Eq. (127)) which marks the approximate boundary between many-particles and few-particles swarms.