Put the ice cubes in a highball glass and drizzle over the grenadine. Mix together the pineapple, lemon and orange juices and add to the glass with the vodka.
Alternatively, put the ice cubes in a cocktail shaker or screw-top jar. Pour the grenadine, fruit juices, grenadine and vodka over the ice and shake until a frost forms. Strain into a highball glass.
Decorate with a lemon slice and serve.