_0$    0.0$\sim$0.0   0.0$\sim$0.0   0.0$\sim$0.0    $X_0$                                  0.0$\sim$0.0    $X_0$                                     $Z_0$                   0.0$\sim$0.0   0.0$\sim$0.0    $Z_0$    0.0$\sim$0.0   0.0$\sim$0.0   0.0$\sim$0.0    $Z_0$    0.0$\sim$0.0   0.0$\sim$0.0   0.0$\sim$0.0   -------- -------------- -------------- --------------    : C