Knit fabric is made from only one set of yarns, all running in the same direction. Sometimes knit fabrics have their yarns running along the length of the fabric, in other cases have their yarns run across the width of the fabric. Knits have the yarns looped together around each other, in order to be held together. Knitting creates ridges in the resulting fabric. Wales are the ridges that run lengthwise in the fabric, courses run crosswise.