WASHINGTON (AP) – Andy Warhol and Prince held center stage in a copyright case before the Supreme Court on October 12 that veered from Cheerios and Mona Lisa analogies to Justice Clarence Thomas’ enthusiasm for the Purple Rain showman. Despite the light nature of the arguments at times involving two deceased celebrities, the issue before the court is a serious one for the art world: When should artists be paid for original work that is then transformed by others, such as a movie adaptation of a book?