The incoming ray is reflected three times, once by each surface, which results in a reversal of direction. To see this, the three corresponding normal vectors of the corner's perpendicular sides can be considered to form a basis (a rectangular coordinate system) (x, y, z) in which to represent the direction of an arbitrary incoming ray, . When the ray reflects from the first side, say x, the ray's x component, a, is reversed to −a while the y and z components are unchanged, resulting in a direction of . Similarly, when reflected from side y and finally from side z, the b and c components are reversed. Therefore, the ray direction goes from to to to , and it leaves the corner reflector with all three components of direction exactly reversed. The distance travelled, relative to a plane normal to the direction of the rays, is also equal for any ray entering the reflector, regardless of the location where it first reflects. thumb|Animation showing the reflected rays in a corner of a cube (corner reflector principle).
The incoming ray is reflected three times, once by each surface, which results in a reversal of direction. To see this, the three corresponding normal vectors of the corner's perpendicular sides can be considered to form a basis (a rectangular coordinate system) (x, y, z) in which to represent the direction of an arbitrary incoming ray, . When the ray reflects from the first side, say x, the ray's x component, a, is reversed to −a while the y and z components are unchanged resulting in a direction of . Similarly, when reflected from side y and finally from side z, the b and c components are reversed. Therefore, the ray direction goes from to to to , and it leaves the corner reflector with all three components of direction exactly reversed. The distance travelled, relative to a plane normal to the direction of the rays, is also equal for any ray entering the reflector, regardless of the location where it first reflects. thumb|Animation showing the reflected rays in a corner of a cube (corner reflector principle).