Realizing this, I knew that the actual space of a room could be broken down and played with by planting illusions of real light (electric light) at crucial junctures in the room's composition.
If you direct your attention to the position of a bird with regard to the wave surface, it will speedily be noticed to be nearly always on the rising side or face of the wave and moving apparently at right angles to the wave's course, but really diagonal to it.

