Two-Tone 'Cocktail' - cooking recipe

Ingredients

4 cups unsweetened pineapple juice, chilled
4 cups tomato juice, chilled
4 lemon slices, thin, halved

Preparation

Into eight 8-oz glasses, pour 1/2 cup pineapple juice.
Tip glass & SLOWLY pour 1/2 cup tomato juice down side of glass [The tomato juice SHOULD end up layered on top of the pineapple juice, NOT MIXED IN!].
Float lemon half-slice on top.
To get fancy, trim with sprig of watercress.
Can be fixed ahead of time, but store in refrigerator NOT MORE THAN 1 HOUR before serving.