A city is a relatively large and permanent settlement. Although there is no agreement on how a city is distinguished from a town within general English language meanings, many cities have a particular administrative, legal, or historical status based on local law.

For example, in the U.S. state of Massachusetts an article of incorporation approved by the local state legislature distinguishes a city government from a town. In the United Kingdom and parts of the Commonwealth of Nations, a city is traditionally a settlement with a royal charter. Historically, in Europe, a city was understood to be an urban settlement with a cathedral.

Cities generally have complex systems for sanitation, utilities, land usage, housing, and transportation. The concentration of development greatly facilitates interaction between people and businesses, benefiting both parties in the process. A big city or metropolis usually has associated suburbs and exurbs. Such cities are usually associated with metropolitan areas and urban areas, creating numerous business commuters traveling to urban centers for employment. Once a city expands far enough to reach another city, this region can be deemed a conurbation or megalopolis.

In computer graphics, z-buffering is the management of image depth coordinates in three-dimensional (3-D) graphics, usually done in hardware, sometimes in software. It is one solution to the visibility problem, which is the problem of deciding which elements of a rendered scene are visible, and which are hidden. The painter's algorithm is another common solution which, though less efficient, can also handle non-opaque scene elements. Z-buffering is also known as depth buffering.

When an object is rendered, the depth of a generated pixel (z coordinate) is stored in a buffer (the z-buffer or depth buffer). This buffer is usually arranged as a two-dimensional array (x-y) with one element for each screen pixel. If another object of the scene must be rendered in the same pixel, the method compares the two depths and chooses the one closer to the observer. The chosen depth is then saved to the z-buffer, replacing the old one. In the end, the z-buffer will allow the method to correctly reproduce the usual depth perception: a close object hides a farther one. This is called z-culling.

Reinhard Friedrich Michael Mey (born December 21, 1942, Berlin) is a German singer-songwriter, known to fans as "Liedermacher". In France he is known as Frédérik Mey.

Mey has released 27 German albums so far by 2009, and consistently releases a new album approximately every two years; his first album was Ich wollte wie Orpheus singen (1967); the most recent studio album is Mairegen (2010). His biggest success to date was Mein Achtel Lorbeerblatt (1972). His most famous song by far is "Über den Wolken" (1974), which has been covered by numerous German artists. Mey is known to embark upon an extensive concert tour every two or three years, with a live album released from each tour.

Reinhard Mey was born on December 21, 1942, in Berlin, Germany, where he spent his childhood. At the age of twelve, he had his first piano lesson, and at the age of fourteen, he got his first guitar. He taught himself how to play the trumpet. During his school years he gained performance experience by playing Skiffle music with friends. In 1965, Mey was offered the chance to perform at a Liedermacher festival at Waldeck Castle, a converted castle ruin. This led to his first recording contract. In 1961, he became part of the group Les Trois Affamés, with Schobert Scholz.