chuang tzu and the butterfly

Chuang Tzu in dream became a butterfly,
And the butterfly became Chuang Tzu at waking.
Which was the real—the butterfly or the man ?

Who can tell the end of the endless changes of things?
The water that flows into the depth of the distant sea
Returns anon to the shallows of a transparent stream.

The man, raising melons outside the green gate of the city,
Was once the Prince of the East Hill.
So must rank and riches vanish.

You know it, still you toil and toil,—what for?

Li Po