Formatting – Creating a Frame with Only Crosses in Two Opposite Corners

formattingframed

Is there one package to produce frames looking like the one above in the following ASCII example ? I don't want dashed lines.

                                              |
                                          ----+--
      Bla, bla, bla, bla, bla, bla, bla, ...  |
      Bla, bla, bla, bla, bla, bla, bla, ...  |
      Bla, bla, bla, bla, bla, bla, bla, ...
      Bla, bla, bla, bla, bla, bla, bla, ...
   |  Bla, bla, bla, bla, bla, bla, bla, ...
   |  Bla, bla, bla, bla, bla, bla, bla, ...
 --+----
   |

PRECISION : I'm looking for something working like standard frames for paragraphs.