From A Window Poem by Christian Wiman

Incurable and unbelieving
in any truth but the truth of grieving,

I saw a tree inside a tree
rise kaleidoscopically

as if the leaves had livelier ghosts.
I pressed my face as close

to the pane as I could get
to watch that fitful, fluent spirit

that seemed a single being undefined
or countless beings of one mind

haul its strange cohesion
beyond the limits of my vision

over the house heavenwards.
Of course I knew those leaves were birds.

Of course that old tree stood
exactly as it had and would

(but why should it seem fuller now?)
and though a man's mind might endow

even a tree with some excess
of life to which a man seems witness,

that life is not the life of men.
And that is where the joy came in.