If you look at a cloud through a window, you will see it floating past the mullions and the window frame, but if you gaze at it without focusing, especially if you are still lying in bed after a good night’s sleep, you may notice that the cloud occasionally stops in the sky, and then jerks back into motion. When you do not focus, you apparently uncouple those parts of your visual apparatus that are concerned with stationary features from those that are concerned with motion. The cloud “stops” when the feature you are gazing at is close to the middle of a windowpane, and it “moves” jerkily as it approaches a mullion or the frame, when a module concerned with motion kicks into action. The most pleasing aspect of such an experience is that you become aware of the fragmented, modular structure of your mind, which otherwise strikes you as seamless and smooth—that is, featureless.