The triangle, the cylinder, the arch, and the fold are examples of shapes that are especially useful when constructing various types of structures. In this film, we take a closer look at how they are used and which shapes are best suited for specific constructions. For example, you'll learn that the triangle is often used in building structures, that the cylinder is strong all around and commonly used in scaffolding or tunnels, that the arch is suitable for supporting heavy loads, and that the folds in corrugated metal sheets make them sturdier.