Chill the fruit punch, pineapple juice and soda for at least 4 hours, or overnight: cold liquids keep the sherbet from melting into soup the second it hits the bowl.

Pour a little pineapple juice into a shallow saucer and the red sanding sugar into a second saucer. Dip the rim of each punch cup first in the juice, then in the sugar, turning to coat evenly, and set the cups upright to dry.

Scoop the lime sherbet into the bottom of a large 2 to 3 quart punch bowl, spacing the scoops so none of them touch.

Pour the chilled green fruit punch slowly over the sherbet, aiming at the side of the bowl rather than straight down, so it builds a cloudy green pool instead of mashing the scoops flat.

Pour in the pineapple juice the same way and give the bowl one gentle stir, just enough to swirl the colors together; the sherbet should still float in visible islands.

Add the lemon-lime soda last, pouring around the edge so the fizz survives. The surface will foam up pale green and settle within a minute, which is how you know it is ready.

Ladle the punch into the sugar-rimmed cups, making sure each cup gets a piece of sherbet, and drop one candy heart onto the foam of each.

Serve at once. The sherbet keeps the punch cold for about an hour in the bowl; after that, float a few fresh scoops on top to revive it.