''c''] to [-''a'', -''b'', ''c''] to [-''a'', -''b'', -''c''] and it leaves the corner with all three components of its direction exactly reversed.

Corner reflectors occur in two varieties. In the more common form, the corner is literally the truncated corner of a cube of transparent material such as conventional optical glass. In this structure, the reflection is achieved either by total internal reflection or silvering of the outer cube surfaces. The second form uses mutually perpendicular