Step 1: Supplies
-ruler and/or straightedge
-scissors (I like good sharp Fiskars, but for paperboard I didn't wanna kill them with it)
-adhesive (I used super glue, but hot glue or another glue properly suited for whatever paperboard you are using. The Loctite super glue that I used had virtually NO set time, so I practiced lining it up a couple of times before gluing to make sure and get half decent results)
-paperboard (or cardboard or whatever, but paperboard is easiest to work with in this case and for these designs)
Step 2: Designing and assembling the box
So, with time on my hands and motivation to draw and cut, i made a second tier for the single, simple box. i wanted it to only touch down in the corners of the bottom box because the cord would be wrapped, and would likely unravel to hit the middle of the sides of the box.
I thought about doing, and decided for sure after using it a couple of times, that I also wanted a finger pull to make it easier to get the top tier out.
If you look at the color coded images they shows which glue flap goes with which flap, although admittedly the folding may be a bit confusing. I'll try to explain and will probably get a bunch of questions anyway... but here goes:
in the middle, the square is the base of the box that holds the cord, marked 4 1/4 and 4 1/4.
--Fold all flaps along the edges of the base, and up. In the second color coded image there is a purple rectangle marking the base.
--On the top, bottom, left and right side there are 2 similar flaps that, once the sides are folded in, should be sticking straight up. Those all need to be folded down.
--Look at the matching colors and fold in and glue the glue flaps to the corresponding piece.
(in anticipation of difficulty with this since I was not able to get pictures, I will start working on CAD pictures to help clarify this step)
Step 3: The End Result (sort of)
Notice the pattern I used for the pull tab- symmetric about the middle, leaving a space for support. then i folded the tabs up, and glued them to the bottom and to each other.
Step 4: One last anal-retentive fix...
So depicted below is the difference and I'll point out how to fix it.