*** OUTSIDE REVERSE FOLD ***
Before you can perform a reverse fold, your model must have already been folded enough so that it has two or more layers of paper. A reverse fold is performed on a part of the model that has two layers of paper and is open one side, closed on the other.
In the outside reverse fold, you fold towards the closed side. The section of paper to be reverse folded is turned inside out so that the sides of the paper that were facing inward now face outward (to do this it may be necessary to open the model partially). Once the fold is completed the part of the paper that has been reversed will lie on the outside of the model. The outside reverse fold is diagramed using a valley fold line and two curved arrows (one with a hollow head) indicating that both sides of the reverse folded section are pulled up at the same time, turning the section inside out.