In two small bowls, combine each gelatin flavor with 1 cup boiling water. Stir 1/2 cup cold water into each. Pour each into an ungreased 9-in. square pan. Refrigerate for 1 hour or until set.
In a large bowl, whisk milk and pudding mixes for 2 minutes. Let stand for 2 minutes or until soft-set. Fold in 2 cups whipped topping.
Set aside 1/4 cup blueberries and 1/2 cup strawberries for garnish. Cut the gelatin into 1-in. cubes. In a 3-qt. trifle bowl or serving dish, layer the strawberry gelatin, half of the cake cubes, the remaining blueberries and half of the pudding mixture.
Top with blue gelatin and remaining cake cubes, strawberries and pudding mixture. Garnish with reserved berries and remaining whipped topping. Serve immediately. Yield: 16-20 servings.