Marbling is a wet stain used to obtain marbled patterns on a surface. Inks are thrown into a vat filled with water and gum tragacanth (the binder used in dry pastels), where they float and form patterns. A stick and a comb are used to guide and shape them until the desired effect is achieved. Then a sheet of paper is delicately placed on the surface and the pattern is transferred onto it. All that remains is to leave it to dry. These sheets are often used as endpapers and paste-downs in bookbinding. Every sheet has a different pattern, which gives the book it covers a unique touch.