D1212121212131323223313233231323331313232213231333132313132311231   >>    D121212121213132322331323323132333131323221323133313231313231123   <<    D1212121212131323223313233231323331313232213231333132313132311233   >>      D1212121212131323223313233231323331313232213231333132313132311232   >>