Engraving is a complex treatment of the glass surface using rotating copper wheels of varying sizes and coated with an oil-based abrasive mixture. The engraved decoration can be left matte or be polished. A distinction is made between relief cutting or carving (cameo) and the more common intaglio, where the projecting elements of the design are engraved more deeply into the glass surface. With cutting, as with wheel-grinding, the glass surface is worked with rotating wheels used either vertically (cutting) or horizontally (grinding). In his cut glass works, just like in his architectural designs of the time, Josef Hoffmann used elements from Classicism and Biedermeier, and he also became interested in colorless cut crystal glass. In a group of stem glasses and flower vessels he combined different bowl shapes with round or square bases and used different types of cutting, particularly the prismatic cut.