Visualization of three field line sets that go through the bald patches to the north-east of p3 (in dark gray, yellow, and light magenta). The two panels show different perspectives of the same field lines. The bottom plane contains a superposition of the NLFFF magnetogram and the image of Fig. 7. To facilitate identification, the field line set visible in the bottom panels of Fig. 8 that is colored according to the value of B_z is repeated here.