In this article, the author presents an overview of concrete as a building material and as an example of a particle composite, and discusses the origins of concrete in ancient Rome. He then describes an activity in which students can cast a concrete patio stone. Students can apply the technological design process, as well as the elements of graphic design, to produce a mosaic pattern on their patio stones in this take-home project. (Contains 3 figures.) ["Patio Stone Project Gives Students a Concrete Learning Experience" was written with Bryan Weber.]