Tint icing. Using rainbow cupcake liners as guide, tint ¾ cup icing each light green, magenta, dark teal and purple using color combinations provided. Combine Leaf Green and Sky Blue icing colors to get light green color shown. Combine Rose and Sky Blue icing colors to get magenta color shown. Combine Teal and Kelly Green icing colors to get teal color shown. Combine Violet and Rose icing colors to get purple color shown.
Using Lemon Yellow and Orange icing colors, tint ¾ icing each yellow and orange.
Prepare 6 decorating bags with tip 6B. Fill separately with light green, magenta, dark teal, purple, yellow and orange icing. Alternating colors, pipe rosette on each cupcake.
Mix sprinkles together in small bowl. Top cupcakes with sprinkles mix.