[17] Repeat step 15. Make sure that edges XY and WZ meet.
[18] Valley fold point X downward so that edge XZ intersects point B. Point B is located at the halfway point of line AC. The illustration for step 19 shows how the model should look once this step has been completed.
[19] Unfold.
[20] To form the head, inside reverse fold along the crease line made in step 18.
