I thought this might be a great alternative to a child's birthday cake.
Frosting (equal amounts of yellow, green, blue, and red)
Curling ribbon (yellow, green, blue, and red)
Frost the cupcakes yellow, green, blue, and red and arrange them on a large platter or cake cardboard.
Tape a length of ribbon to the bottom of each cupcake.
Tie all the ribbons together and curl the ends as shown.