A set of bedding usually consists of a flat or fitted bed sheet that covers the mattress; a flat top sheet; either a blanket, quilt, or duvet, sometimes with a duvet cover which can replace or be used in addition to the top sheet; and a number of pillows with pillowcases, also referred to as pillow shams. (See § Terminology for more info on all these terms.) Additional blankets, etc. may be added to ensure the necessary insulation in cold sleeping areas. A common practice for children and some adults is to decorate a bed with plush stuffed animals, dolls, and other soft toys. These are not included under the designation of bedding, although they may provide additional warmth to the sleeper.