Furniture Design Ydin Stool by Franck Divay Ydin stool can be mounted by yourself, 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. Feet are made with scrap wood coming from a stairs manufacturer, easily machined using traditional woodworking techniques and finally oiled. The seat is simply moulded in a lasting fiber-reinforced UHP Concrete. Only 5 dissociable parts to be flat packed and ready to be shipped to final customers, is another sustainability argument.