  We construct examples of smooth periodic solutions to the Magnetohydrodynamic
equations in dimension 2 with positive resistivity for which the topology of
the magnetic lines changes under the flow. By Alfv\'en's theorem this is known
to be impossible in the ideal case (resistivity = 0). In the resistive case the
reconnection of the magnetic lines is known to occur and has deep physical
implications, being responsible for many dynamic phenomena in astrophysics. The
construction is a simplified proof of [3] and in addition we consider the case
of the forced system.
