Increasingly complex and changing forms of mobility and fluidity are emerging. Vellum is made of strips of woven wool (in the Saharan Maghreb and among the Maghrebis), an assembly of tanned skins (by the Touareg), a woven material made of braided fronds of the doum palm (by the Touareg and Tubu), or nowadays, imported white cotton or plastic tarps. It comprises most of the fertile lands of Algeria.