PetscSF Object: 2 MPI processes
  [0] Number of roots=1, leaves=2, remote ranks=2
  [0] 0 <- (0,0)
  [0] 1 <- (1,0)
  [1] Number of roots=1, leaves=2, remote ranks=2
  [1] 0 <- (1,0)
  [1] 1 <- (0,0)
Vec Object: 2 MPI processes
Process [0]
0.
1.
Process [1]
1.
0.
Vec Object: 2 MPI processes
Process [0]
10.
11.
Process [1]
11.
10.