Anise liqueurs have the interesting property of turning from transparent to cloudy when added to water: the oil of anise remains in solution in the presence of a high concentration of alcohol, but crystallizes when the alcohol concentration is reduced.
Layered drinks are made by floating different-coloured liqueurs in separate layers. Each liqueur is poured slowly into a glass over the back of a spoon or down a glass rod, so that the liquids of different densities remain unmixed, creating a striped effect.