CoachSection restoration undoes, on a cross-section drawn parallel to the direction of tectonic transport, the deformation it shows, event by event in the reverse order, keeping the lengths of the beds and the areas of the units in the plane of the section. A pin line is a line across the beds, placed where they did not slip along each other (in the undeformed foreland, or on the axial surface of a symmetric fold), which is taken to be perpendicular to the beds in the restored section; lengths are measured from it. In the kink-band method the folds are drawn as straight limbs of constant bed thickness joined at sharp hinges, whose axial surfaces bisect the angle between the limbs; each bed is then a broken line, whose length is the sum of its straight segments.
