Flashed glass is glass with a thin layer of colored glass applied to one side.
The base glass is usually clear or white.
Areas of the colored glass are then removed to create typically vibrant designs. Copper wheel
cutting and sandblasting are just two methods for removing areas of color.
Flashing glass should not be confused with "casing" glass -- a technique in which the additional
layer(s) of glass are much thicker than with flashing.