Yield: 18 servings (3 points per serving for blue, green and purple)
Preheat oven to 325 degrees F.
Add the cake mix and diet root beer to a large mixing bowl. Mix together using a hand held mixer on medium for 2 minutes.
Add the cake batter to a 9x13 baking pan and bake according to the directions on the box, then let the cake cool.
Use the handle of a wooden spoon to poke 40-50 holes in the cake.
Mix together the pudding and skim milk according to the directions on the box, then spread the pudding over the cake. Use a rubber spatula to smooth it out and make sure the pudding gets into the holes.
Cover the cake and refrigerate for two hours.
Put the Werther's candy in a zip up bag. Use a rolling pin or meat mallet to break the candy into tiny pieces.
Add the Cool Whip to the top of the cake and spread it out evenly. Sprinkle the candy pieces on top.