What is common to all the editions of the "Nights" is the initial frame story of the ruler Shahryār and his wife Scheherazade and the framing device incorporated throughout the tales themselves. The stories proceed from this original tale; some are framed within other tales, while others are self-contained. Some editions contain only a few hundred nights, while others include 1,001 or more. The bulk of the text is in prose, although verse is occasionally used for songs and riddles and to express heightened emotion. Most of the poems are single couplets or quatrains, although some are longer.