Top: visualization of strong (weak) magnetic (velocity) structures (dark and light isosurfaces correspondingly) in the kinematic regime. Streamlines (coming from the up-right corner) converge first to an a-type stagnation point (center of the box), and then diverge and are twisted around weak velocity tubes as soon as they reach their neighbourhood. Middle: strong vorticity isosurfaces, null vortex points and vortex lines. Bottom: weak magnetic field (visualized only in the center of the box as a transparent isosurface), strong magnetic sheets and magnetic field lines. Most of the field lines are folded at the center of the box and then add to the neighboring sheets. In all figures, the arrows show the direction of the lines.