Decrease value of ix to avoid that possible swap is skipped. If e.g. ix = 0, ichoice will be 0 as well. If the edge swapping succeeds, the new intersected[0] will be the old intersected[1]. However, as ix is now 1 and so ichoice will be 1 as well, it will now check the new intersected[1], which is the old intersected[2]. Old intersected[1] is now skipped. In test "unable_to_recover_edge.geo", there are 5 edges intersected, but as one possible edge is skipped all the time and 2 other edges cannot be swapped, the other two edges keep on going from one configuration to another configuration and back again. With this fix, the test will now succeed.