Spirograph with added twists. Instead of just using points, use polygons, lines and circles with different blends, colors and transparencies to get very pleasing designs. And with many other options such as size, line width, etc one can literally make millions of designs. From kids to adults can enjoy their own creations. Be warned some designs wont be as pleasing as others.
Added benefits - You can store, retrieve and do autoplay of all your designs.