Glass can be manufactured in different colors by adding different metals into the initial mix. When glass of different colors are pieced together to make a larger unit, it is referred to as stained glass. A form of decorative glass, the most commonly recognizable use was as windows in places of worship, though it can also be found in other structures as well, including restaurants. Stained glass can replicate specific images or offer more abstract designs. More recently, it has also been used in three-dimensional artwork by some glass artisans. In traditional stained glass windows, the colored glass pieces are held together by lead framework.