diff --git a/18-context-mngr/mirror.py b/18-context-mngr/mirror.py
index 67782ff..ba31944 100644
--- a/18-context-mngr/mirror.py
+++ b/18-context-mngr/mirror.py
@@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context.
 While active, the context manager reverses text output to
 ``stdout``::
 
-# BEGIN MIRROR_DEMO_1
+# tag::MIRROR_DEMO_1[]
 
     >>> from mirror import LookingGlass
     >>> with LookingGlass() as what:  # <1>
@@ -18,12 +18,12 @@ While active, the context manager reverses text output to
     >>> print('Back to normal.')  # <5>
     Back to normal.
 
-# END MIRROR_DEMO_1
+# end::MIRROR_DEMO_1[]
 
 
 This exposes the context manager operation::
 
-# BEGIN MIRROR_DEMO_2
+# tag::MIRROR_DEMO_2[]
 
     >>> from mirror import LookingGlass
     >>> manager = LookingGlass()  # <1>
@@ -40,11 +40,11 @@ This exposes the context manager operation::
     >>> monster
     'JABBERWOCKY'
 
-# END MIRROR_DEMO_2
+# end::MIRROR_DEMO_2[]
 
 The context manager can handle and "swallow" exceptions.
 
-# BEGIN MIRROR_DEMO_3
+# tag::MIRROR_DEMO_3[]
 
     >>> from mirror import LookingGlass
     >>> with LookingGlass():
@@ -63,12 +63,12 @@ The context manager can handle and "swallow" exceptions.
       ...
     NameError: name 'no_such_name' is not defined
 
-# END MIRROR_DEMO_3
+# end::MIRROR_DEMO_3[]
 
 """
 
 
-# BEGIN MIRROR_EX
+# tag::MIRROR_EX[]
 class LookingGlass:
 
     def __enter__(self):  # <1>
@@ -89,4 +89,4 @@ class LookingGlass:
         # <11>
 
 
-# END MIRROR_EX
+# end::MIRROR_EX[]
diff --git a/18-context-mngr/mirror_gen.py b/18-context-mngr/mirror_gen.py
index 379e8ab..457955a 100644
--- a/18-context-mngr/mirror_gen.py
+++ b/18-context-mngr/mirror_gen.py
@@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context manager.
 While active, the context manager reverses text output to
 ``stdout``::
 
-# BEGIN MIRROR_GEN_DEMO_1
+# tag::MIRROR_GEN_DEMO_1[]
 
     >>> from mirror_gen import looking_glass
     >>> with looking_glass() as what:  # <1>
@@ -16,12 +16,12 @@ While active, the context manager reverses text output to
     >>> what
     'JABBERWOCKY'
 
-# END MIRROR_GEN_DEMO_1
+# end::MIRROR_GEN_DEMO_1[]
 
 
 This exposes the context manager operation::
 
-# BEGIN MIRROR_GEN_DEMO_2
+# tag::MIRROR_GEN_DEMO_2[]
 
     >>> from mirror_gen import looking_glass
     >>> manager = looking_glass()  # <1>
@@ -38,12 +38,12 @@ This exposes the context manager operation::
     >>> monster
     'JABBERWOCKY'
 
-# END MIRROR_GEN_DEMO_2
+# end::MIRROR_GEN_DEMO_2[]
 
 """
 
 
-# BEGIN MIRROR_GEN_EX
+# tag::MIRROR_GEN_EX[]
 
 import contextlib
 
@@ -61,4 +61,4 @@ def looking_glass():
     sys.stdout.write = original_write  # <6>
 
 
-# END MIRROR_GEN_EX
+# end::MIRROR_GEN_EX[]
diff --git a/18-context-mngr/mirror_gen_exc.py b/18-context-mngr/mirror_gen_exc.py
index 9dcc560..c446918 100644
--- a/18-context-mngr/mirror_gen_exc.py
+++ b/18-context-mngr/mirror_gen_exc.py
@@ -4,7 +4,7 @@ A "mirroring" ``stdout`` context manager.
 While active, the context manager reverses text output to
 ``stdout``::
 
-# BEGIN MIRROR_GEN_DEMO_1
+# tag::MIRROR_GEN_DEMO_1[]
 
     >>> from mirror_gen import looking_glass
     >>> with looking_glass() as what:  # <1>
@@ -16,12 +16,12 @@ While active, the context manager reverses text output to
     >>> what
     'JABBERWOCKY'
 
-# END MIRROR_GEN_DEMO_1
+# end::MIRROR_GEN_DEMO_1[]
 
 
 This exposes the context manager operation::
 
-# BEGIN MIRROR_GEN_DEMO_2
+# tag::MIRROR_GEN_DEMO_2[]
 
     >>> from mirror_gen import looking_glass
     >>> manager = looking_glass()  # <1>
@@ -38,7 +38,7 @@ This exposes the context manager operation::
     >>> monster
     'JABBERWOCKY'
 
-# END MIRROR_GEN_DEMO_2
+# end::MIRROR_GEN_DEMO_2[]
 
 The context manager can handle and "swallow" exceptions.
 The following test does not pass under doctest (a
@@ -46,7 +46,7 @@ ZeroDivisionError is reported by doctest) but passes
 if executed by hand in the Python 3 console (the exception
 is handled by the context manager):
 
-# BEGIN MIRROR_GEN_DEMO_3
+# tag::MIRROR_GEN_DEMO_3[]
 
     >>> from mirror_gen import looking_glass
     >>> with looking_glass():
@@ -57,7 +57,7 @@ is handled by the context manager):
     ytpmuD ytpmuH
     Please DO NOT divide by zero!
 
-# END MIRROR_GEN_DEMO_3
+# end::MIRROR_GEN_DEMO_3[]
 
     >>> with looking_glass():
     ...      print('Humpty Dumpty')
@@ -73,7 +73,7 @@ is handled by the context manager):
 """
 
 
-# BEGIN MIRROR_GEN_EXC
+# tag::MIRROR_GEN_EXC[]
 
 import contextlib
 
@@ -98,4 +98,4 @@ def looking_glass():
             print(msg)  # <4>
 
 
-# END MIRROR_GEN_EXC
+# end::MIRROR_GEN_EXC[]