Decorate cakes. Prepare decorating bag with tip 2D and desired icing. Place cake on turntable.
Green Cake: Starting at base of cake, pipe stars around cake. Continue until covered.
Pink Cake: Starting at base of cake, pipe vertical rows of zig-zags around cake. Pipe rosettes to cover top of cake.
Blue Cake: Spatula ice top of cake smooth. Starting at base of cake, pipe horizontal rows of loops around cake, moving tip down and back up to starting position. Continue until covered. Pipe small swirls around top of cake. Sprinkle with rainbow nonpareils.