Yet its position is more or less completely central: its upper edge is exactly on an imaginary line running half way between the top and the bottom of the painting, it hangs right in the middle of the far wall (or at least in the middle of the portion we can see); it ought, therefore, to be governed by the same lines of perspective as the picture itself; we might well expect the same studio, the same painter, the same canvas to be arranged within it according to an identical space; it could be the perfect duplication.