On each of 2 large serving trays, arrange 12 cupcakes as shown in diagram. Frost shell of one turtle with chocolate frosting. Frost head and feet with green frosting. (Push cupcakes together slightly to frost entire turtle, not just individual cupcakes.) Pipe green frosting on chocolate shell to create turtle design. Add 2 candies for eyes; add pupils using chocolate frosting. Add nostrils with chocolate frosting or miniature chocolate candies. Add red string licorice for mouth (trimming to fit) and green licorice for tail.