A flat-pack cardboard box

Nets and Views

The box stands three-dimensional on the shelf, but it left the factory as a flat piece of board. Nothing was added in between, nothing was cut away — it was only folded. So the surface of the box was two-dimensional all along. The real question is what holds that flat piece together: why can the net come out in one piece, and why do no two faces ever land on top of each other?