The Viking Runes. The eldest runestones, inscribed with Norse runes, date from the century. These were the Elder Futhark runes. However, the most of the runestones were created during the late Viking Age and thus inscribed with theYounger Futhark runes.
The Ouroboros or Uroborus often represents self-reflexivity or cyclicality, especially in the sense of something constantly re-creating itself, the eternal return, and other things perceived as cycles that begin anew as soon as they end (compare Phoenix).