Stained glass refers to either the material of colored glass or the art of working with it. The copper foil method is the most common method we use today. After completing the window design on paper the pieces are numbered and transferred to the glass. The glass is then cut and the edges ground down as necessary to allow the pieces to fit like a puzzle. When the foil method is used the glass is then wrapped in copper foil and soldered together on both sides. A patina is often applied to darken the lead before it is polished and framed.