Something happened here. That's what makes these white walls and this gray window gleam some indigo glow.

Something happened here years ago, and it left these four corners to coruscate forever its soft sad light.

If you're standing in the corner, which you are, then you can see how Shannon must have seen the room before he etched a cross into the cushioned crease of paint and pressed his hand against it, knowing his only hope was to cross. Letting his linens swing in the lingering breeze on the tree limb, he left an open window, an empty room, and a pile of books on the floor.

Shannon lived in this room before you.
He left a pile of books, a cross, and an indigo glow.