A robin that taps against the window.
Not against the window but against the egg in which it sits
and the egg breaks into two.
Not the egg but the ice that breaks off downwards from Greenland.
A black sea in which white expanses drift.
Not expanses but mountains.
Not ice but granite.
Which the robin needs to sharpen its beak on.
Its beak stronger than the egg.
Stronger than Greenland.