<Li> Railroads: Engine drivers and rail transit operators use sand to improve the traction of wheels on the rails . </Li> <Li> Recreation . Playing with sand is a favorite beach time activity . One of the most beloved uses of sand is to make sometimes intricate, sometimes simple structures known as sand castles . Such structures are well known for their impermanence . Sand is also used in children's play . Special play areas enclosing a significant area of sand, known as sandboxes, are common on many public playgrounds, and even at some single family homes . </Li> <Li> Roads: Sand improves traction (and thus traffic safety) in icy or snowy conditions . </Li> <Li> Sand animation: Performance artists draw images in sand . Makers of animated films use the same term to describe their use of sand on frontlit or backlit glass . </Li>

How sand is formed in rivers in marathi