Put your hand over one eye. You lose depth perception, giving the world a more 2D kind of look. Now look around the room. Imagine all of the smaller things are gone. For example, if you are dreaming you are in your living room you might see the sofa, the pillows, the television, the rug, the coffee table. But you won't see the remote control, or the television guide, or the coffee stain someone left behind.