Three-dimensional rendering of the magnetic field lines in the box around the two flux tubes at different times. Far left panel: field lines at t = 12 400 s (onset of first kink instability). Middle left panel: field lines at t = 12 500 s. Middle right panel: field lines at t = 12 550 s (second loop disruption). Far right panel: field lines at t = 12 600 s. The change in the field line connectivity during the evolution of the MHD cascade is highlighted by the different colours.