Isometry

fold the net into a box

A flat cardboard net lies on the table. Fold its flaps up one at a time, each to its mark, in the right order, until it stands as a box. Forty nets in five chapters, from a simple tray to boxes that tuck, nest and slide into each other.

On iPhone and iPad you fold with your finger. On iPhone Duo the phone's own hinge does the folding: open and close the phone, and the flap follows. On Apple TV you fold with the Siri Remote: circle the clickpad to turn the flap, click to crease it.