Mirror (Off-axis): Place anywhere in the simulation window. Click at the desired location, then drag out the mirror in the direction and to the length you desire. Later on, with Select depressed, you can change the direction and length of the mirror by click-and-dragging on its hotspots (see figure below). You may place up to three of these mirrors.

The mirror reflects all incident light on the blue side and absorbs all light on the black side. An alternative view of this object is available.