Subject matter and genres have ranged from adventure, detective and humor strips to dramatic strips with soap opera situations, such as "Mary Worth". A continuity strip employs a narrative in an ongoing storyline. Other strips offer a gag complete in a single episode, such as "Little Iodine" and "Mutt and Jeff". The Sunday strip is contrasted with the daily comic strip, published Monday through Saturday, usually in black and white. Many comic strips appear both daily and Sunday, in some cases, as with "Little Orphan Annie", telling the same story daily and Sunday, in other cases, as with "The Phantom", telling one story in the daily and a different story in the Sunday. Some strips, such as "Prince Valiant" appear only on Sunday. Others, such as "Rip Kirby", are daily only and have never appeared on Sunday. In some cases, such as "Buz Sawyer", the Sunday strip is a spin-off, focusing on different characters than the daily.