Salt/Pepper Mortar and pestleDESIGN: Sigve Knutson & Thomas Ballouhey. Sigve Knutson and Thomas Ballouheys objects combine minimalism with the aesthetics of the Stone Age, like with this rough shaped grinder consisting of a grinding ball that rolls in a preconceived circular trench. While the grinder looks like its been beaten out of solid rock it is actually made of cast iron protected by diazotization against corrosion. MATERIALS: Cast Iron.