The raster bar (also referred to as rasterbar or copperbar) is an effect used in demos that displays animated bars of colour, usually horizontal, which additionally might extend into the border, a.k.a. the otherwise unalterable area (assuming no overscan) of the display. Raster bars, especially horizontal, were very common in demos for the Commodore 64, Commodore Amiga, Atari ST, ZX Spectrum and Amstrad CPC.