Sofa bed.
Sofa bed. These are pieces in which the back of the sofa swings down flat with the seat to form the sleeping surface. Some sofa beds have bedding boxes for storage of bedding. There are two types: the one-piece, where the back and seat are upholstered as a unit, supplying an unbroken sleeping surface; and the two-piece, where back and seat are upholstered separately (see Figure 11 of this part).