Three-dimensional view of field lines before and after they have reconnected. Right: distribution along the PIL of post-flare loops at t = 45   t_A. Each field line is color-coded accordingly with the altitude z = 0.1,0.2,...,1,1.1 of its apex. Left: progenitor field lines at t = 0, plotted from the same footpoints at z = 0 of same the post flare loops as drawn in the right panel. In both panels, a differential shear is present, with a shear decreasing away from the PIL.