Here is a couple of great ways to use straws and pipe cleaners to teach geometry. I have students create snowflakes and then discuss symmetry. To teach how to find the diagonal of the rectangular prism, have students create a 3-4-5 prism and then cut paper triangles to fit inside the prism. They can then prove to themselves that d = sqrt(l^2 + h^2 + w^2)!!!!!!! Enjoy!!!!