In Bologna, Italy, Mario Cucinella Architects partnered with a 3D-printing company WASP to build homes that can be made entirely out of clay. The homes are hive-shaped, with a glass door, window, and circular skylight to allow in natural light. Cucinella drew his ideas from potter wasps, who use local materials to construct their homes. The structures are created with two 3D-printing arms that lay down 350 layers of clay and rice chaff for insulation. Another neat feature of these homes is that if they ever need to be knocked down, the only waste would be plumbing, gas, and electrical components; the earth simply returns to where it came. Cucinella said the idea of the city must be challenged, proposing one alternative for an eco-friendly, urban lifestyle with this architecture design.