D1212121212131323223313233231323133313231323331311331323132313232212121   >>    D121212121213132322331323323132313331323132333131133132313231323221212   <<    D1212121212131323223313233231323133313231323331311331323132313232212123   >>      D1212121212131323223313233231323133313231323331311331323132313232212122   >>