A first load (L1) is put on the upper leg (606) to create a contact area (619) between the front segment (610) and the front segment (618). The contact area (619) has a center point (601) located a distance (p1) from the front end (602). An upper forward segment (621) pulls away from a lower forward segment (623) immediately adjacent to the front end (602) to create a loop (625a). The first load (L1) is progressively increased to a second load (L2) and the center point (601) is rolled back from the distance (p1) to a distance (p2) from the front end (602). The segments (621) and (623) expand the loop (625a) to a loop (625b).
