2.4 folding.

Folding transforms a sheet to a diversity of folding structures.

“In geometry the net of a polyhedron is an arrangement of edge-joined polygons in the plane which can be folded (along edges) to become the faces of the polyhedron. (…) For any given polyhedron that is unfolded into a net, many different equivalent nets can be formed depending on the choices of which edges are joined and which are separated.”

http://en.wikipedia.org/wiki/Net_(polyhedron)