In a small bowl, combine one package flavored gelatin and one envelope unflavored gelatin. Stir in 1 cup boiling water until dissolved. Let mixture cool slightly for 3-5 minutes.
Pour mixture into a 13-in. x 9-in. dish coated with cooking spray.
Refrigerate until set but not firm, about 20 minutes.
In small bowl, combine the condensed milk and 1 cup boiling water.
In another bowl, sprinkle two envelopes unflavored gelatin over cold water; let stand for 1 minute. Stir in 3/4 cup boiling water. Add to sweetened condensed milk mixture.
Spoon 1 cup of the creamy gelatin mixture over the first flavored gelatin layer. Refrigerate until set but not firm, about 25 minutes.
Repeat from beginning of recipe twice alternating flavored gelatin with creamy gelatin layers.
Make sure to let the dissolved gelatin sit for a few minutes before spooning over previous layer. This will keep the layers "pure".
Chill each layer until set but not firm before spooning next layer on top.
Make final flavored gelatin and spoon over top.
Refrigerate for 2 hours after finishing last layer before cutting into 1-in. squares.
Serve and enjoy!