Flammé yarns are a kind of novelty yarn. It is generally a loose or untwisted core wrapped by at least one other strand. The extra element can be a metallic thread, or a much-thicker or much-narrower strand of yarn, or yarn that varies between thick and thin. Some companies have come to put twin yarns on the market to show off combinations of one regular yarn and novelty yarns in assorted colors or even two different types of novelty yarns.