Crewel, also called crewelwork, is a form of embroidery done with woolen yarn. Most crewel has designs stitched on a background of plain, sturdy cloth. The yarn, which consists of two woolen threads twisted together loosely, is also called crewel. Crewel can be used to create almost any design. Many crewel embroideries show flowers and vines arranged in graceful patterns. Crewel may include any embroidery stitch.