Positions of stars at 200 Myr (top) and 300 Myr (bottom) for W0 (left column) and W45 (right column) colour-coded by metallicity. The white area outlines the disc (R = 30 kpc, z = ±2 kpc). The picture of tail star formation can be confusing even the case of face-on stripping, where due to projection effects stars on the outskirts of the galaxy appear to be located in its centre. The clean picture of the metallicity gradients, where stars located farther from the disc have lower metallicity due to the prior ISM–ICM mixing, is complicated by the fact that even at the same height stars can be moving in different directions, with some falling back on the galaxy. At later times, this leads to oscillations of stars around the galaxy disc.