Figure 9.

Two sequences of zipping reconnection with $N=4$ flux tubes that are different from the case of northward propagation depicted in Figure 6. (a) Southward propagation produces similar results but with twist distributed in the opposite order, so that $D_{+}{C}_{-}$ has twist ${\Phi }_1$ rather than ${\Phi }_3$. (b) In a converging sequence, the third reconnection event (shown in (c)) occurs between two flux ropes ($A_{+}{B}_{-}$ and $C_{+}{D}_{-}$) with twist ${\Phi }_1$.