Strength of different shapes of paper

We made a triangular prism shape, a tent shapes, a cube shape, and a cylinder shape out of computer paper.   We then stacked books on them .  The tent one could not support one book nor could the triangular prism, but the column and the cube could hold one. Then 2 books were tried, but then the cube failed. The cylinder made of computer paper went onto hold 5 books. Then, Megan suggested that a column made out of cardstock would be even stronger.  And it was.  It held up a lot of books, including her kingfisher dictionary.  Her and I were amazed!! She talked about it later , saying to her dad, " it held up the dictionary, could you believe it!!