A neat riddle describing a well, round as an apple and too deep even for all the king's horses to fill. Good for a guessing game before bath time.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
As round as an apple, as deep as a cup,
And all the king's horses can't fill it up.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition