What is Warp and Weft?
In weaving, the weft (sometimes woof) is the term for the thread or yarn which is drawn through, inserted over-and-under, the lengthwise warp yarns that are held in tension on a frame or loom to create cloth. Warp is the lengthwise or longitudinal thread in a roll, while weft is the transverse thread. A single thread of the weft, crossing the warp, is called a pick. Terms do vary (for instance, in North America, the weft is sometimes referred to as the fill or the filling yarn). Each individual warp thread in a fabric is called a warp end or end. The weft is a thread or yarn usually made of spun fibre. The original fibres used were wool, flax or cotton. Today, man-made fibres are often used in weaving. Because the weft does not have to be stretched on a loom in the way that the warp is, it can generally be less strong. The weft is threaded through the warp using a "shuttle", air jets or "rapier grippers." Hand looms were the original weaver's tool, with the shuttle being threaded through alternately raised warps by hand. A useful way of remembering which is warp and which is weft is: 'one of them goes from weft to wight'. -Wikipedia
"All twill weaves are produced by floating the weft elements over more than one warp at a time to create a raised pattern of color and texture. Three twill-weave techniques were used by both Navajo and Pueblo weavers: plain twill forming diagonal floats; herringbone twill, in which the diagonal floats alternate direction to form a vertical zigzag or chevron pattern; and a diamond twill, in which the herringbone patterns are woven in such a manner as to create concentric diamond patterns." Reference: Kaufman, Alice and Christopher Selser. The Navajo Weaving Tradition 1650 to the Present: page 138.