Copper Bars

The "Copper" is a coprocessors located in Agnus Custom Chip of the Commodore Amiga Computer. It allows to write values to hardware registers (e. g. the background color at dff0180) at a defined vertical position on the screen, and thus to implement cool graphical effects without consuming a single CPU cicle. A common use are the so-called "Copper-Bars", which are cool-looking vertical color-patterns that were popular in scene demos and cracker intros. My demo mimics this effect using pure CSS without a single line of JavaScript.