LeonardoΓÇÖs spotlight is basically a box with a lens in front. A door in the side allows a light source, such as a candle, to be placed inside. (There must also be a small air hole somewhere in the box to allow air inside, so the candle will not be extinguished.) The lens simply concentrates and magnifies the rays of the light. Leonardo did not say what his spotlight might be used for, but we can imagine it illuminating a scene to be painted, providing light for reading or highlighting an actor in a play.
