Even a closed door has a knob you could turn to see what happens.

From Alfred’s journal

The shed behind the blue house has been shut since the frost, and I have perched on its handle most mornings without thinking about it. Today a boy of maybe nine came down the yard, stood in front of it, and read the sign his father had hung there, and then he walked away. The sign says KEEP OUT, but the padlock has been hanging open on its hasp since October; I have watched the wind swing it. For years I took a door to be the argument and the lock to be the proof, when the lock was only an ornament and nobody had checked. Even a closed door has a knob you could turn to see what happens. He came back twice in the afternoon and read it again both times, as though the words might have softened.