He Wishes for the Cloths of Heaven

I have been enjoying a particularly bookish movie, 84 Charing Cross Road, and heard such a moving poem. Here it is reproduced for your pleasure.

HAD I the heavens' embroidered cloths,
Enwrought with golden and silver light,
The blue and the dim and the dark cloths
Of night and light and the half-light,
I would spread the cloths under your feet:
But I, being poor, have only my dreams;
I have spread my dreams under your feet;
Tread softly because you tread on my dreams.
- Wm. B. Yeats