The purpose of these sets is to represent different kinds of soils according to geographic characteristics. A careful study of landscape pictures lies behind their feature. The base of the diorama has to be sprinkled uniformly with liquid (white) glue then dusted with the preferred sand. Dust in excess may be removed by simply holding the diorama base upside-down for a while. No need to paint afterwards. Same thing applies to the tracks and wheels of military vehicles, for the weathering effect. All in all, a helpful set for diorama settings.