Grease 13 x 9 pan with margarine and dust lightly with flour. Prepare, mix and
bake cake mix according to package directions. Cool cake for 15 minutes.
With large fork, make holes in cake about every 1/2 inch.
Pour gelatin into mixing bowl. Add cup of boiling water and use scraper to mix
thoroughly until gelatin is completely dissolved. Use measuring cup to pour
gelatin over cake. (It will run down into holes, making sliced cake have red
Chill cake in refrigerator 3 to 4 hours.
Cover tray with aluminum foil.
Put about one inch of warm water in kitchen sink. Take pan out of refrigerator
and dip bottom (don't let water come up over sides) into water for about 10
seconds. Put large tray on top of cake, and invert.
Frost sides and top with whipped topping. Arrange strawberries and
marshmallows in alternating rows for stripes, leaving upper left for field of
blueberries. Chill again until time to serve.