Do yourself a favor and buy it, if you are into graphics editing.

Back in the 90s, video cards could only render 256 colors at a time, so a palette of selected colors was used. But the programmer could change this palette at will, and all the onscreen colors would instantly change to match. It was fast, and took virtually no memory. This demo is an implementation of a full 8-bit color cycling engine, rendered into an HTML5 Canvas in real-time.