is it possible to have a surface designed in such a way that ,when it is struck by a ray of light , the reflected light (fort he sake of example) takes a horizontal direction. My idea is that the light would propagate in a plane which would be more or less parallel to the plane of the surface that the light had struck.. I am not asking whether it is possible to direct the beam in a parallel direction to any given surface bit if it can be done to the actual surface it has impacted . If it had struck a tile the roof of a house ,for example, could the slate be so designed (or painted) as to reflect the light in the direction of the adjoining slates instead of the angle of incidence that I learned about in school? I realise that this sounds impossible but ,with so much changing in physics over the years I wonder if this could actually be done.