He could not be captured,
He could not be bought,
His running was rhythm,
His standing was thought;
With one eye on sorrow
And one eye on mirth,
He galloped in heaven
And gambolled on earth. And only the poet
With wings to his brain
Can mount him and ride him
Without any rein,
The stallion of heaven,
The steed of the skies,
The horse of the singer
Who sings as he flies.

Pegasus, St. 3 & 4, p. 181 - The New Book of Days (1961)