Image source: http://www.sli.unimelb.edu.au/aura/images/nbox.jpg
Cardboard and plastic boxes are commonly used for storage and shipping because
they can be sealed easily, and a group of them can be arranged so that there is not any space between
Image source: http://doityourself.com/photos/brick.jpg
Cement bricks are often in the shape of a box so they can be stacked easily
to form a wall.