As the bird approaches the glass does not its shadow move from the ground to the bricks of the wall beneath the window, if any, and then up the glass of the window itself to meet the bird at the point of collision? Do not bird, image, shadow (and image of shadow?) come together like Shade, Kinbote and Gray (and? - VN, reader?)? But Shade does not experience himself as the bird, rather as its shadow. ???