Graffiti Graffiti Graffiti (both singular and plural; the singular "graffito" is very rare in English except in archeology) is writing or drawings made on a wall or other surface, usually without permission and within public view. Graffiti ranges from simple written words to elaborate wall paintings, and it has existed since ancient times, with examples dating back to ancient Egypt, ancient Greece, and the Roman Empire. In modern times, paint (particularly spray paint) and marker pens have become the most commonly used graffiti materials. In most countries, marking or painting property without the property owner's permission is considered defacement and vandalism,
Singular point of an algebraic variety at that is lower than the rank at other points of the variety. Points of "V" that are not singular are called non-singular or regular. It is always true that almost all points are non-singular, in the sense that the non-singular points form a set that is both open and dense in the variety (for the Zariski topology, as well as, in the case of varieties defined over the complexes, for the usual topology). In case of a real variety (that is the set of the points with real coordinates of a variety defined by polynomials with real coefficients), the