Comet 67P shape formation by sub-catastrophic collisions. Shown is an example of an SPH calculation of an impact on a rotating ellipsoid. After the initial disruption, subsequent re-accumulation leads to the formation of two lobes. This processes may include the possible formation of layers. The two lobes are gravitationally bound and collide with each other within ~ one day forming a bi-lobed structure. The final shape is also shown in Fig. 4. Initial conditions: off axis (impact point + dy; see Fig. 1) impact of a R_p = 200 m impactor with a velocity of V = 300 m/s on a target with axis ratio 0.7 (mass M_t = 1.4 × 10¹³ kg) and rotation period of T = 6 h. The rotation axis is along the y axis (see Fig. 1).