 If the incident beam is linearly polarized at some other inclination, the emerging beam is elliptically polarized with one principal axis in the plane of reflection, and vice versa.The rhomb usually takes the form of a right parallelepiped — that is, a right parallelogram-based prism.If the incident ray is perpendicular to one of the smaller rectangular faces, the angle of incidence and reflection at the "next" face is equal to the acute angle of the parallelogram.