I am an outsider to this group. I'm a journalist and am working on a piece about theoretical math/geometry. Simply put, when a napkin is folder in such a way to increase its perimeter is that strictly theoretical? Like, the physical limitations of the world (tension and width of cloth) make it impossible to increase the perimeter.

Can someone help me understand what is really being discussed when geometry people discuss the folding of a ruble or napkin?

-thanks