Sand in nature
If we view a folded mountain range we see what once was primeval ocean bed, in other words sand and mud transformed into solid rock by pressure, heat or chemical reactions, pushed up by the continental shift. That kind of natural Sandpictures are moving and constantly changing even though it is concealed for the eyes of our short live span. Those processes take hundreds of millions of years and would become a monumental natural movie when taken in time laps.
Arid zones take 20 % of the land masses on earth (polar zones excluded). Of those again 20 % are covered with sands. The sandiest deserts are those of Australia, of which approx. 50 % are sandy deserts. The biggest desert in one patch is the Rub' al Khali - the empty quarter on the Arabian peninsula. A Sandpicture of gigantic dimensions. In a sand desert we can get a glimpse of the moving formations. Especially if you ever discovered a sand storm. The vastness and silence in deserts is so fascinating that it is said deserts make you addicted. I recommend everybody trying it out. Beginners drug: Sandpictures!