On a morning in Pinar de Campoverde, Costa Blanca, Spain, Alison Betts (Member 36,977) spied translucent puzzle-piece clouds, which are Altocumulus stratiformis perlucidus in their infancy. The puzzle pieces, referred to as cloudlets, have edges formed by narrow regions of sinking air. Over time, the clouds will thicken as the Altocumulus layer matures. Either that, or they’ll just dissipate away again to leave a completely blue sky. We won’t claim to know which. We’d only be bluffing.