Sample panels of the photospheric B_z and of the magnetic-footpoint horizontal speeds. Black (white) correspond to negative(positive) polarity B_z saturated in ±300 Gauss. The overplotted blue arrows correspond to the horizontal speeds of the magnetic footpoints. The longest arrows correspond to a magnitude of 1 km s⁻¹. The purple line corresponds to the PIL of the photospheric B_z. The green box corresponds to the region in which magnetic flux cancellation takes place. Consecutive time-steps are 86.9 s apart. The associated movie is available online.