Line six or seven shot glasses on a work surface or a big bowl of crushed ice (if making a snow cone). This can get messy.
Add the grenadine to a cocktail shaker. Add enough crushed ice to the ice until the shaker is three-quarters full. Slowly pour the pineapple juice over the back of a spoon or ice scoop into the shaker. Then add the gin and a splash of curacao. This will create layers. Strain the liquid into the shot glasses. If making ice cones, pour over the crushed ice, making sure there is enough space for all of the colors.
From Food Network Kitchens