A term that can be applied very generally to the disposition of objects in an exhibition (the hanging of paintings, the arrangement of sculptures, and so on), but which also has the more specific meaning of a one-off work (often a large-scale assemblage) conceived for and usually more or less filling a specific interior (generally that of a gallery). This type of work has various precedents, including the room-filling Merz constructions of Kurt Schwitters, but it was not until the 1970s that the term came into common use and not until the 1980s that certain artists started to specialize in this kind of work, creating a genre of ‘Installation art’. In the 1970s installations were often impermanent and could be seen as part of the movement against the collectable art ‘object’ that was so fashionable at the time. However, many installations are now intended for permanent display, and even some of the most unlikely works have proved collectable. A well-known example is 20:50 (1987) by the British sculptor Richard Wilson (b 1953), consisting of a room filled with used sump oil; this was created for the Matt's Gallery, London, but it was subsequently resited at the Royal Scottish Academy, Edinburgh, and it is now in the Saatchi Collection, London.