Ydin stool can be mounted without using special tools, thanks to a simple interlocking system. The 4 identical feet are placed in no particular order and the concrete seat, acting as the keystone, keeps everything in place. Easily machined feet are made with scrap wood coming from a stairs manufacturer and finally oiled. The seat is moulded in a lasting fiber-reinforced concrete. Only 5 dissociable parts to be flat packed and ready to be shipped, is another sustainability argument.