Wallpaper is a kind of material used to cover and decorate the interior wall
A wall is a usually solid structure that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into rooms, or protects or delineates a space in the open air...

s of homes, offices, and other building
In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...

s; it is one aspect of interior decoration. It is usually sold in rolls and is put onto a wall using wallpaper paste
Wallpaper paste
Wallpaper adhesive or wallpaper paste is a specific adhesive, based on modified starch or methylcellulose, used to fix wallpaper to walls.Wallpaper pastes have a typical shear thinning viscosity and a high wet adhesive tack...

. Wallpapers can come plain (so that it can be painted), textured (such as Anaglypta
Lincrusta was invented in 1877 by Frederick Walton. It became an instant success because it was the first washable wallcovering and appealed to the Victorians because of its sanitary properties as well as its durability and ornate effects. Originally made on a linen backing, it was however, quite...

), or with patterned graphics.

Wallpaper printing techniques include surface printing
Surface printing
Surface printing is the oldest automated printing method still in use today. Surface machines lay down very heavy amounts of ink. Because the ink is pushed onto the paper, the images are not as crisp as the other methods. Also, there is no drying stage between laying down each color, so the...

, gravure printing
Rotogravure is a type of intaglio printing process; that is, it involves engraving the image onto an image carrier...

, silk screen-printing
Screen printing is a printing technique that uses a woven mesh to support an ink-blocking stencil. The attached stencil forms open areas of mesh that transfer ink or other printable materials which can be pressed through the mesh as a sharp-edged image onto a substrate...

, rotary printing
Rotary printing press
A rotary printing press is a printing press in which the images to be printed are curved around a cylinder. Printing can be done on large number of substrates, including paper, cardboard, and plastic. Substrates can be sheet feed or unwound on a continuous roll through the press to be printed and...

, and digital printing
Digital printing
Digital printing refers to methods of printing from a digital based image directly to a variety of media. It usually refers to professional printing where small run jobs from desktop publishing and other digital sources are printed using large format and/or high volume laser or inkjet printers...

. Mathematically speaking, there are seventeen basic patterns, described as wallpaper group
Wallpaper group
A wallpaper group is a mathematical classification of a two-dimensional repetitive pattern, based on the symmetries in the pattern. Such patterns occur frequently in architecture and decorative art...

s, that can be used to tile an infinite plane.