The Hammerskins are one of the oldest hardcore racist skinhead groups in the United States and have a history of violence. Their logo and primary symbol, appropriated from Pink Floyd's "The Wall," consists of two crossed hammers, usually superimposed over a cogwheel. The symbol typically appears in red, white, and black, the colors of the Nazi flag. In some cases the hammers and cogwheel appear over a red, black and white-colored shield. In the United States, the Hammerskins differentiate themselves regionally, such as the Confederate Hammerskins and Western Hammerskins and can sport regional variations of this logo, such as a version incorporating the Confederate flag. The Hammerskins have spread to several countries outside the United States and such variants appear there, as well, often incorporating national colors or symbols.