Preheat oven to 350 degrees F. Grease and flour 2 8x8x2-inch or 2 9x9x11/2-inch baking pans; set aside. Prepare cake mix according to package directions. Divide batter in half. Tint each half of batter a different color using liquid food coloring (use only a few drops to keep the batter a pastel color). Place one color batter in each prepared pan. Bake for 25 minutes or until a toothpick inserted near the center comes out clean. Cool in pans on wire racks for 10 minutes. Remove from pans. Cool completely.
Prepare frosting according to package directions. Spread about 1/2 cup frosting on top of one cake layer. Top with remaining cake layer. Frost top and side of cake layers with remaining frosting. Arrange wafer candies on top and sides of cake in a random polka-dot pattern. Arrange candy-coated chocolate pieces around bottom edge of cake, if desired. Makes 12 servings.