As she walked her dog after work one day, Marianne de Snoo (Member 64,238) spotted peach-coloured clouds that looked to be sculpted in Art Deco style over the village of Busquístar, Andalusia, Spain. The clouds are known as Altocumulus lenticularis, and they form when moist airflows lift to pass over hills or mountains. In stable atmospheric conditions, rising and dipping waves develop in the flow downwind of the peaks, with lenticularis clouds forming where the air cools most at the crests of these invisible waves of air. The Art Deco styling comes courtesy of alternating layers of moister and drier air, which cause the cloud to appear in a stacked formation. This stacked effect is known formally as lenticularis duplicatus and more generally with the French for a ‘stack of plates’: pile d’assiettes. ‘Sometimes, life is just perfect,’ said Marianne. ‘Being in your favorite spot at the right time, with the ones you love, seeing the most amazing cloud formation of your life.’