It can be made up of a single sheet of paper that is printed on both sides and folded in half , in thirds , or in fourths ( called a leaflet ) . It may consist of a single sheet of paper that is printed on both sides and folded in half , in thirds , or in fourths ( called a leaflet ) , or it may consist of a few pages that are folded in half and saddle stapled at the crease to make a simple book .