Kinematics of magnetic "null" points (X-points/dissipative regions and O-points/plasmoids). Red circles denote O-point positions, black crosses the X-point positions, and green asterisks show the position of those X-points that are magnetically connected to the photosphere. The three bottom panels show detailed views of selected rectangles and represent typical processes of X- and O-point dynamics: bifurcation (null-pair creation) and merging (null-pair annihilation).