First and second loops for the same model as in Fig. B.1 are fitted by ellipses for simulation with mass ratio 3. The left panel is at 5.6 Gyr and the right panel shows loops at 8.6 Gyr. Particles belonging to different loops are naturally selected by their distance to the centre in the tail-forming epoch (3.5 Gyr). Green indicates particles with small elevations (see Fig. B.1, bottom-left panel), and black points indicate large elevation particles. Green points populate the second loop, while black points show particles of the first loop. Particles coming back from the tidal tail begin to outline the first loop and then enter in the second loop. The parameters of the fitted ellipses are given in the top left corner of each panel. They are the semi-major axis a, semi-minor axis b, focus distance, eccentricity, and position angle.