Combine sugar, corn syrup, and water. Bring to a boil, stirring constantly. Reduce heat and cook to hard ball stage. Combine beaten egg whites and gelatin - beat until mixture forms stiff peaks. Pour hot syrup slowly into egg whites, beating until candy loses gloss and holds shape. Fold in coconut and nuts (optional). Pour into greased 9 inch square pan. Top with rows of chopped nuts and coconut.