The animation helps understanding a 3-dimensional map-making process. You may easily understand the map is made of a combination of two projections (mapping), from a sphere to a "inflated-tetrahedron" then from the "inflated-tetrahedron" to a tetrahedron so as to reduce errors.
It shows how to cut and unfold the tetrahedron to make a rectangular map. It shows how to tile the maps as well and to frame a new world map while changing its center.