How do you construct a prime pyramid?

Pyramid math is a special technique used to teach basic addition skills through an illustration of 10 boxes stacked like a pyramid (four at the bottom, then three, then two, then one) and adding the numbers in adjacent boxes until reaching the top. The activity can be modified to use multiplication as well - - multiplying the numbers at the bottom until reaching the product at the top. Working backward (i. e., starting with the top number) provides the factors.