Tint icing. While the cake layers cool, tint icing. Combine Violet and Burgundy food coloring for purple shown.
Divide icing into four 1 cup portions: tint light teal, orange, black and purple. Fit 3 piping bags with the tip 233, and fill one of each with teal, orange and purple icings. Fit 1 piping bag with tip 2 and fill with white icing. Set aside.