An art undone

I wander lonely as a cloud, That floats on high o'er vale and hill, When suddenly it springs to mind, That someone's already done this. So now instead of thieving it, As most of you expect of me, I struggle hard for something fresh, Untainted yet by words of man. I wait for words to spring to mind, And rhymes with meaning or of wit, Of places old and pastures new, Or maybe from forgotten pasts. But nothing stirs within my head, And so I'm left with empty page, To fill with writings of my fight, To give the world an art undone.