If the surface is more likely to fall within the compound and reflection of light, and then the external surface is horizontal and vertical reflection of light fall on the same planar surface within.
If the surfaces are vertical and horizontal reed reflection of light and the surface is oriented vertically incident and reflected on the same plane with the inner surface.
If the surface within the fall Kok and light reflection of the impact surface will be the impact of ะท้อน and of light in the same plane with the surface inside.