Butter the sides of a 2-quart saucepan. In it combine sugar, corn syrup, water, and salt. Cook over medium heat, stirring constantly, until sugar is dissolved. Continue cooking to 265 (hard ball stage), without stirring. Mixture should boil gently over entire surface. Remove from heat. Stir in butter or margarine. Add flavoring and food coloring, if desired. Pour into a buttered 15x10x1 inch pan. Cool about 20 minutes or till easily handled. Butter hands and pull candy until difficult to pull. Cut into fourths. Pull each piece into a long strip about 1/2" thick. With buttered scissors, cut taffy into bite-sized pieces. Wrap each piece in plastic wrap and store overnight.