Textiles are formed by weaving, knitting, crocheting, knotting , tatting, felting, or braiding. Cro-tatting combines needle tatting with crochet. Knotting involves tying threads together and is used in making tatting and macrame. Many people consider cro-tatting more difficult than crochet or needle tatting. The cro-tatting tool is a tatting needle with a crochet hook at the end. A lark's head is called a double stitch in tatting. Some tatting designs incorporate ribbons and beads. There are two basic techniques for needle tatting. There are currently two manufacturers of tatting needles. Smaller sizes (40 and up) are often used for tatting jewelry and fine lace. The craft of tatting is composed primarily of lark's head knots over carrier threads. The mercerization process strengthened cotton threads and spread their use in tatting. Pottery included, among others, tatting ware and shelly ware.