A simple way to make a box creature to to cut out an identical front and back, and then connect them with a longer, thick strip of cardboard (the strip becomes he sides of the box.) You can also make identical sides and use the strip to connect them (the strip becomes the front, back, top, and bottom of the box.) We used the formula below to get the basic shape of our owl creature that inhabited the box fort. See a time-lapse video of its creation here. We also used this technique when we created this 12′ piñata. Chris Sandon was a collaborator in making the piñata.