Quote from The Locked Room from The New York Trilogy written by Paul Auster

By some obscure train of thought, it made me think back to when we were very small--no more than four or five years old. Fanshawe's parents had bought some new appliance, a television perhaps, and for several months Fanshawe kept the cardboard box in his room. He had always been generous in sharing his toys, but this box was off limits to me, and he never let me go in it. It was his secret place, he told me, and when he sat inside and closed it up around him, he could go wherever he wanted to go, could be wherever he wanted to be. But if another person ever entered his box, then its magic would be lost for good. I believed this story and did not press him for a turn, although it nearly broke my heart. We would be playing in his room, quietly setting up soldiers or drawing pictures, and then, out of the blue, Fanshawe would announce that he was going into his box. I would try to go on with what I had been doing, but it was never any use. Nothing interested me so much as what was happening to Fanshawe inside the box, and I would spend those minutes desperately trying to imagine the adventures he was having. But I never learned what they were, since it was also against the rules for Fanshawe to talk about them after he climbed out.

Paul Auster
The New York Trilogy