Street art is unofficial and independent visual art created in public locations for public visibility. Street art is associated with the terms "independent art", "post-graffiti", "neo-graffiti", and guerrilla art, but is not public art. Common forms and media for street art include spray paint graffiti, stencil graffiti, wheatpasted poster art, sticker art, street installations, and sculpture. Video projection and yarn bombing have also gained some popularity near the turn of the 21st century. When street art is applied to walls or barriers, it can generally also be called a 'mural'.