During 1997, BK revamped its French fries in North America. The improved fries were coated with a layer of potato-based starch, giving the fries a crisp shell that maintained its texture longer. The company introduced them in a series of advertisements that claimed the new fries tasted better than McDonald's fries in consumer taste comparisons. Other ads featured Mr. Potato Head in a series of demographically-targeted commercials. The fries were in research and development for over two years and already had been available in several markets when the advertising campaign began. In Europe, BK also sells potato wedges, a type of French fry that is thick-cut and wedge-shaped. In 1991, the company introduced Twister fries, spiral-cut fries with a spicy coating, as part of a promotional push. Part of the product's appeal was they were served in a paper drink cup as opposed to the normal fry carton. The product was designed as a short-term promotion that would be periodically reintroduced.