A reed is a firm-stemmed grass, with a hollow stem that looks like bamboo. It is a sturdy material and reed mats are used as walls for structures and roofs. The reed is first split and shaved before it is woven in a twill weave into mats. They are made starting at one corner and plaiting or weaving is done diagonally. Long strips are folded at the middle and another strip is inserted crosswise, which is in turn folded and the next strip is again inserted crosswise and so on. The creases of the crosswise strips form the edges of the mat. Reeds are also used to make very sturdy baskets.