An ellipse has two focal points. When the light source is placed at the first focal point of an ellipsoidal reflector, the light rays will be reflected through the second focal point. Optically, this second focal point serves as a directional light source. This enables the second focal point to be used as a gate where gobos and shutters can be inserted to shape the beam. Ellipsoidal reflectors are used in most profile-spots, and in special floodlights like scoops.