Ice cookies 1 day in advance. Prepare Color Flow icing following recipe directions. Divide and tint icing in four shades each: yellow, orange, burgundy, rust and ivory.
Place cookies on cooling grid over parchment-covered cookie sheet. Use thinned Color Flow icing in cut decorating bags to cover cookies. For some, pipe multicolor stripes. For others, pipe stripes in light and dark shades of the same color. For some, use toothpick to drag and swirl colors together. Tap to smooth and remove excess icing. Use spatula to smooth edges. Let dry 24 hours.