Stir 1 cup of the boiling water into each flavor gelatin in separate bowls at least 2 minutes until completely dissolved. Stir 1 cup cold water into each bowl.
Pour into separate 8- or 9-inch square pans.
Refrigerate 4 hours or until firm.
Cut gelatin in each pan into 1/2-inch cubes.
Layer alternating gelatin flavors and 1-1/2 cups of the whipped topping in 8 dessert glasses.