Step 2: Assemble The Frame
The octagonal frame is made from two sections; a top piece that is strapped to you, containing the electronics and important bits, and a detachable bottom portion that attaches to the top half. The lid slides into the top and holds the shape.
For both halves you need to cut 8 pieces of cardboard, four that are 3.5 inches wide, for the corners, and four that are 17.75 inches wide, for the sides. The top half is as long as the box you have is, and the second part is as long as it needs to be to extend below the first section and cover you legs. You need at least 8 inches of clearance so the costume can pass over stairs. I am 6' 2" so my second section is 29 inches long and I still have two inches of headroom under the lid.
Cut all the pieces using a metal ruler and a box cutter and then tape all eight sections together, alternating sizes. Repeat for the second part.
For the lid I stacked to pieces of cardboard on top of each other, secured them with doublestick foam, with the folds in each layer of cardboard at right angles to each other( the costume frame becomes wider than the box I used with the addition of the 45 degree corner pieces). I then secured foam in the corners to keep the costume's shape.