When Arthur Curtis first sees his wife in his office at the very end of the shot, the film goes in reverse for less than a second. You can see Arthur Curtis move backward and Mrs. Curtis' handbag swing back abruptly - both in the exact same motion as when going forward. See more
You're looking at a tableau of reality, things of substance, of physical material: a desk, a window, a light. These things exist and have dimension. Now this is Arthur Curtis, age thirty-six, who also is real. He has flesh and blood, muscle and mind. But in just a moment we will see how thin a line separates that which we assume to be real with that manufactured inside of a mind.