The Angle of a Landscape — Window

The Angle of a Landscape-1
That every time I wake-
Between my Curtain and the Wall
Upon an ample Crack-

Like a Venetian-waiting-5
Accosts my open eye-
Is just a Bough of Apples-
Held slanting, in the Sky-

The Pattern of a Chimney-9
The Forehead of a Hill-
Sometimes-a Vane's Forefinger-
But that's-Occasional-

The Seasons-shift-my Picture-13
Upon my Emerald Bough,
I wake-to find no-Emeralds-
Then-Diamonds-which the Snow

From Polar Caskets-fetched me-17
The Chimney-and the Hill-
And just the Steeple's finger-
These-never stir at all-
(F.578/J.375)
[1–3] Landscape, Between, Curtain, Wall:: a window.
[4] an ample Crack:: the window itself is a wide crack on the wall.
[5] Venetian:: a Venetian window; Venetial blind.
[9–12] Chimney, Hill:: views outside her window.
[13] shift my Picture:: change the window view.
[15] find no Emeralds:: green in summer and white in winter.
[16] Diamonds:: icicles.
[17–19] Polar Caskets:: the view of things covering with snow in her window as if fetched from the polar region.
[20] never stir:: a hint to solve the riddle, picture changed in the window but the window was never stirred.