Imagine you have a wooden structure the size and shape of a shoebox, and that you nailed this structure to a white wall. Over the course of the day you observe light from an adjacent window illuminating the structure, which casts a variety of shadows as the sun moves across the sky. Then someone enters the room and places a baseball inside the structure. Then someone enters the room and attaches a light fixture to the top of the structure so that a bulb can shine down on the baseball at all times.
What conclusions can be drawn from this?
