This past Christmas I received the most beautiful paper snowglobe from my dear friend, Cathie. Only, it was far more than a snowglobe for I had never seen anything quite like it. It was intricate to say the least. And, it actually folded flat from a 3D sphere in order to place into an envelope. It is displayed on a shelf in my craft room and is greatly admired and often inquired about during stamp camps.
Coincidentally, my mother-in-law received the following Easter and birthday cards in her honor this past month which featured a similar style that I found equally as lovely and unique.
After a little bit of research I have learned that these are called "sliceforms." According to a Google search, "sliceforms" are geometric models constructed from interlocking sets of planar pieces. By creating two sets of slotted pieces ("slot-from-the-top" and "slot-from-the-bottom" sets) that intersect at right angles, one can link the two sets together to form attractive models of surfaces and solids. The best recent references on the subject are by the British mathematician/artist John Sharp, whose books "Sliceforms" and "Surfaces" include numerous beautiful examples done in colored paper.
I'll continue to do more research into this paper art form, because I think it would make for a great (though seemingly difficult) techniques class!