Around the mould are built the sides (or ribs), which are flat pieces of wood curved by means of careful heating. Early violin makers used strips of "tiger" maple wood to enhance the beauty of the violin, and most luthiers preferred wood harvested in Northern Italy. The completed "garland" of ribs, blocks, and linings is removed from the mould to allow attachment of the separately carved top and back. When the body is complete, the neck, which is carved out of a separate piece of wood (usually maple), is set in its mortise to complete the basic structure of the instrument, after which it is varnished. Maple is considered the choice wood because of its strength and ability to withstand the stresses exerted on it by playing.