Megaripples in sand deserts (IMAGE) Universität Leipzig Caption It’s all in the mix: In megaripples in sand deserts (bottom), the composition of coarse and fine grains of sand (top) varies depending on the wind. For the first time, researchers have demonstrated a universal grain-size ratio hidden in that composition. Credit Photo: Hezi Yizhaq and Klaus Kroy Usage Restrictions No License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.