Pour the cranberry juice into the glass, filling about 1/3 of the way.
Slowly pour the blue gatorade on top of the ice (if you pour it around the sides of the glass and it hits the cranberry juice directly without filtering over the ice, it won't create separate layers) and let it flow down until it fills the cup another 1/3 of the way (so now the glass should be 2/3 full).
Finally, slowly pour the Sprite Zero on the ice and let it slowly flow down to create the final layer. Serve immediately.
Layering the Drinks: the method behind this drink is choosing 3 (or more!) drinks with varying sugar content and layering the drinks with the highest sugar on the bottom working up to the no-sugar drink on top. For instance, I used cranberry juice with 30g sugar for the bottom layer, blue gatorade with 16g sugar for the middle layer and Sprite Zero with 0g sugar for the top layer.