 Okay, so construction materials and this has a lot to do with insulation. Stability is not that much of an issue because the stability if we don't talk high-rise is not a big issue. Well, researching this issue very long. So before I started studying for civil engineering, I learned the profession of bricklaying. And so building houses with bricks is pretty nice. But then later I learned that making these bricks, burning them, costs lots of energy. And so now I'm very much in favor of Lohm bricks, air-dried Lohm bricks. And we work together with Marius Birik, who has a company, a Lohm building company near Frensburg in the very north of Germany. And he has a lot of experience. He worked with GIZ in Ethiopia for many years. They have a long tradition in Lohm building. So he brought together a European tradition with African, East African tradition. And so he became a very, very good Lohm builder. And we do also the Lohm stoves together with him. So he developed some wood gas stoves with Lohm. So we like that very much. And so we did some work with him. We learned from him. And we worked together for the Ethiopia project. And this is something where we do have, well, a material that is absolutely wonderful. So many areas do have good Lohm. And the Lohm bricks are very much dependent on the composition of the Lohm. So you must have a specific composition between clay, silt, and sand. And if this is in a good range, you make bricks, you air-dry them, and you could build 100 floors buildings with air-dried Lohm bricks. So it is very, very stable. And we don't want to go for 100 floors, I think. This is not very ecological from the beginning. But if we go one floor, two or three floors, this is absolutely sufficient.