diff --git a/doc/manual/src/architecture/architecture.md b/doc/manual/src/architecture/architecture.md
index f113cbf4d..0df4fbc68 100644
--- a/doc/manual/src/architecture/architecture.md
+++ b/doc/manual/src/architecture/architecture.md
@@ -11,20 +11,25 @@ Nix consists of [hierarchical layers].
 
 ```
 +---------------------------------------------------------------+
-| Nix                                                           |
-|                 [ commmand line interface ]------,            |
+| Nix             .-------------------------.                   |
+|                 | commmand line interface |------.            |
+|                 '-------------------------'      |            |
 |                              |                   |            |
 |                          evaluates               |            |
 |                              |                manages         |
 |                              V                   |            |
-|                 [ configuration language  ]      |            |
+|                 .-------------------------.      |            |
+|                 | configuration language  |      |            |
+|                 '-------------------------'      |            |
 |                              |                   |            |
-| +----------------------------|-------------------V----------+ |
-| | store                 evaluates to                        | |
-| |                            |                              | |
+|                         evaluates to             |            |
+|                              |                   V            |
+| +----------------------------|------------------------------+ |
+| | store                      |                              | |
 | |            referenced by   V       builds                 | |
-| | [ build input ] ---> [ build plan ] ---> [ build result ] | |
-| |                                                           | |
+| | .-------------.      .------------.      .--------------. | |
+| | | build input |----->| build plan | ---->| build result | | |
+| | '-------------'      '------------'      '--------------' | |
 | +-----------------------------------------------------------+ |
 +---------------------------------------------------------------+
 ```
@@ -54,24 +59,28 @@ The result of a build task can be input to another build task.
 
 ```
 +----------------------------------------------------------------------------------+
-| store           ..............................................                   |
+| store            - - - - - - - - - - -  - - - - - - - - - - -                    |
 |                 : build plan                                 :                   |
-|                 :                                            :                   |
-| [ build input ]---instructions-,                             :                   |
-|                 :              |                             :                   |
+| .-------------. :                                            :                   |
+| | build input |---instructions-.                             :                   |
+| '-------------' :              |                             :                   |
 |                 :              v                             :                   |
-| [ build input ]--------->[ build task ]-instructions-,       :                   |
-|                 :                                    |       :                   |
+| .-------------. :        .------------.                      :                   |
+| | build input |--------->| build task |-instructions-.       :                   |
+| '-------------' :        '------------'              |       :                   |
 |                 :                                    v       :                   |
-| [ build input ]---instructions-,              [ build task ]--->[ build result ] |
-|                 :              |                     ^       :                   |
-|                 :              v                     |       :                   |
-| [ build input ]--------->[ build task ]--------------'       :                   |
+| .-------------. :                             .------------. :  .--------------. |
+| | build input |---instructions-.              | build task |--->| build result | |
+| '-------------' :              |              '------------' :  '--------------' |
+|                 :              v                     ^       :                   |
+| .-------------. :        .------------.              |       :                   |
+| | build input |--------->| build task |--------------'       :                   |
+| '-------------' :        '------------'                      :                   |
 |                 :              ^                             :                   |
-|                 :              |                             :                   |
-| [ build input ]----------------'                             :                   |
-|                 :                                            :                   |
-|                 :............................................:                   |
+| .-------------. :              |                             :                   |
+| | build input |----------------'                             :                   |
+| '-------------' :                                            :                   |
+|                 :_ _ _ _ _ _ _ _ _ _ _  _ _ _ _ _ _ _ _ _ _ _:                   |
 +----------------------------------------------------------------------------------+
 ```