This simple tradition came from a parent in my classroom 6 years ago. Once I demonstrate how to tack the milk carton and graham cracker sides down, I let the students get completely creative in their designs. We use plain white frosting in a tub, so marshmallows and lighter candy work best. I let students problem solve and insert math language as we discuss, slope, weight and shapes. I introduce and use 3-D shape vocabulary such as, rectangular prism and triangular prism. In geometry, the pentagonal prism is a prism with a pentagonal base. It is a type of heptahedron with 7 faces, 15 edges, and 10 vertices.