Harvard Beets

1/2 Cup sugar
1 1/2 Teaspoons cornstarch
1/4 Cup cider vinegar
1/4 Cup water
4 Cups sliced or cubed cooked beets
2 Tablespoons margarine
Mix the sugar, cornstarch, vinegar, and water in a pot and boil for 5 minutes. Add the beets, toss well, and let stand for 30 minutes. Just before serving, add the margarine and reheat to the boiling point. Serves 8.