NOTE: It is often the case in the solution to magnetic problems that the field values are
discontinuous across a boundary. In this case, FEMM determines which side of the boundary
will be plotted based on the order in which points are added. For example, if points are
added around a closed contour in a counterclockwise order, the plotted points will lie just to
the inside of the contour. If the points are added in a clockwise order, the plotted points will
lie just to the outside of the contour. The implication to our example problem is that the
contour along the r=0 should be defined in order of decreasing z (i.e. counterclockwise so
that the plotted points will lie inside the solution domain instead of outside it, where the
field values are not defined).