This box model was named "Sturdy" because its unique design gives it at least two layers on every surface and a self-locking method that makes it solid and difficult to unfold.
A big part of the fun of folding boxes is the choice of paper. Most any type of paper works fine for this model designed with 8 1/2" X 11" sheets. Rectangles cut in the ratio of 3 X 4 also work.
The picture shows 3 examples using 8 1/2 X 11 papers: a snakeskin-pattern gift wrap; a blue, leaf-pattern vinyl wallpaper; and a green fabric-covered wallpaper.
Folding Hint: When finished folding, you can add tensile strength to the top edges of this box (and any box folds). Lay any side edge on a tabletop with the model's top, folded edge facing you. Make a slight curl of the top edge, inward and parallel to the top edge and perform this step on all the top edges. The curl is hardly noticeable but adds strength and stability.
The model may be folded and taught non-commercially. Please contact me for other permissions. Enjoy!