I love brightly colored Royal Icing on sugar cookies, with each cookie being different. Some of these designs are the result of wet-on-wet mixing of multiple colors, and others, the result of hand-held piping. The links that appear here point to examples of mandalas and symmetrical designs.
Until now, I imagined that there were instructions somewhere on the web on how to make individual wet-on-wet designs, but did not know where to find them until seeing a demonstration on Pinterest. There I discovered that this type of art is called Ebru, which refers to an ancient craft of Turkish Marbling.
The marbeling is created by floating paints on thickened water, then transferred to paper or cloth. Click this Google Link asking for “Turkish Marbling Art” for many reference articles and video tutorials. Mentally translate this information to Royal Icing flow-on-flow techniques.
See many examples on Instagram’s firdevscalkanoglu. Although I can’t read a word on this page, I did learn that you can take classes on the craft. Here are a few links to videos found on that page: