diff --git a/examples/wave/wave-eager-mpi.py b/examples/wave/wave-eager-mpi.py
index fc09cbd5f2718c39449fdfbaf4deaef6bbadc8ae..a6ca4381c9c84345d5d7eec64e470c43e05a20e1 100644
--- a/examples/wave/wave-eager-mpi.py
+++ b/examples/wave/wave-eager-mpi.py
@@ -180,8 +180,6 @@ def main():
     def rhs(t, w):
         return wave_operator(discr, c=1, w=w)
 
-    rank = comm.Get_rank()
-
     t = 0
     t_final = 3
     istep = 0
@@ -190,7 +188,9 @@ def main():
 
         if istep % 10 == 0:
             print(istep, t, discr.norm(fields[0]))
-            vis.write_vtk_file("fld-wave-eager-mpi-%03d-%04d.vtu" % (rank, istep),
+            vis.write_parallel_vtk_file(
+                    comm,
+                    f"fld-wave-eager-mpi-{{rank:03d}}-{istep:04d}.vtu",
                     [
                         ("u", fields[0]),
                         ("v", fields[1:]),
diff --git a/examples/wave/wave-min-mpi.py b/examples/wave/wave-min-mpi.py
index bca2610199ed1cf50ae0c178d28caf1579730e3c..95bcab7034cc1adc6a3feb30f700aa49d804ae55 100644
--- a/examples/wave/wave-min-mpi.py
+++ b/examples/wave/wave-min-mpi.py
@@ -124,8 +124,6 @@ def main(write_output=True, order=4):
     from time import time
     t_last_step = time()
 
-    rank = comm.Get_rank()
-
     for event in dt_stepper.run(t_end=final_t):
         if isinstance(event, dt_stepper.StateComputed):
             assert event.component_id == "w"
@@ -135,11 +133,9 @@ def main(write_output=True, order=4):
             print(step, event.t, norm(u=event.state_component[0]),
                     time()-t_last_step)
             if step % 10 == 0:
-                vis.write_vtk_file(
-                        "fld-wave-min-mpi-%03d-%04d.vtu" % (
-                            rank,
-                            step,
-                            ),
+                vis.write_parallel_vtk_file(
+                        comm,
+                        f"fld-wave-min-mpi-{{rank:03d}}-{step:04d}.vtu",
                         [
                             ("u", event.state_component[0]),
                             ("v", event.state_component[1:]),