Trirectangular tetrahedron in the context of Corner reflector

A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat reflective surfaces. It reverses the direction of an incoming wave with being translated by reflections on the three orthogonal sides. The three intersecting surfaces often are triangles (forming a tetrahedron) or may have square shapes. Radar corner reflectors made of metal are used to reflect radio waves from radar sets. Optical corner reflectors, called corner cubes or cube corners, made of three-sided glass prisms, are used in surveying and laser ranging.