diff --git a/markdown.html b/markdown.html
index d26dc5ee8..722b46e2f 100644
--- a/markdown.html
+++ b/markdown.html
@@ -431,7 +431,7 @@
 <h2 id="ioccc-markdown-guidelines-version">IOCCC Markdown guidelines version</h2>
 </div>
 <p class="leftbar">
-These <a href="markdown.html">IOCCC markdown guidelines</a> are version <strong>28.3 2025-04-28</strong>.
+These <a href="markdown.html">IOCCC markdown guidelines</a> are version <strong>28.4 2025-04-28</strong>.
 </p>
 <p><strong>IMPORTANT</strong>: Be sure to read the <a href="next/rules.html">IOCCC rules</a> and <a href="next/guidelines.html">IOCCC
 guidelines</a>.</p>
@@ -468,14 +468,22 @@ not apply to other markdown files), <strong>PLEASE</strong> start at level three
 to 3 for new sections. For instance:</p>
 <pre><code>    ### Section 0
     ...
-    #### First subsection of section 0
+    #### 1st subsection of section 0
     ...
-    ##### Second subsection of section 0
+    ##### 1st sub-subsection of the 1st subsection of section 0
     ...
-    ###### Third subsection of section 0
+    #### 2nd subsection of section 0
+    ...
+    ##### 1st sub-subsection of the 2nd subsection of section 0
+    ...
+    ##### 2nd sub-subsection of the 2nd subsection of section 0
+    ...
+    ###### 1st sub-sub-subsection of the 2nd sub-subsection of the 2nd subsection of section 0
     ...
     ### Section 1
     ...
+    ### Section 2
+    ...
     Etc.</code></pre>
 <div id="name">
 <div id="anchor-name">
diff --git a/markdown.md b/markdown.md
index 84e94ff5c..9fb704570 100644
--- a/markdown.md
+++ b/markdown.md
@@ -7,7 +7,7 @@
 </div>
 
 <p class="leftbar">
-These [IOCCC markdown guidelines](markdown.html) are version **28.3 2025-04-28**.
+These [IOCCC markdown guidelines](markdown.html) are version **28.4 2025-04-28**.
 </p>
 
 **IMPORTANT**: Be sure to read the [IOCCC rules](next/rules.html) and [IOCCC
@@ -66,14 +66,22 @@ to 3 for new sections. For instance:
 ``` <!---markdown-->
     ### Section 0
     ...
-    #### First subsection of section 0
+    #### 1st subsection of section 0
     ...
-    ##### Second subsection of section 0
+    ##### 1st sub-subsection of the 1st subsection of section 0
     ...
-    ###### Third subsection of section 0
+    #### 2nd subsection of section 0
+    ...
+    ##### 1st sub-subsection of the 2nd subsection of section 0
+    ...
+    ##### 2nd sub-subsection of the 2nd subsection of section 0
+    ...
+    ###### 1st sub-sub-subsection of the 2nd sub-subsection of the 2nd subsection of section 0
     ...
     ### Section 1
     ...
+    ### Section 2
+    ...
     Etc.
 ```
 
diff --git a/sitemap.xml b/sitemap.xml
index 8f4f355be..0025433a9 100644
--- a/sitemap.xml
+++ b/sitemap.xml
@@ -15490,11 +15490,11 @@
 </url>
 <url>
     <loc>https://www.ioccc.org/markdown.html</loc>
-    <lastmod>2025-04-28T20:25:52+00:00</lastmod>
+    <lastmod>2025-04-28T20:35:33+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/markdown.md</loc>
-    <lastmod>2025-04-28T20:25:25+00:00</lastmod>
+    <lastmod>2025-04-28T20:35:23+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/news.html</loc>
@@ -15598,7 +15598,7 @@
 </url>
 <url>
     <loc>https://www.ioccc.org/status.html</loc>
-    <lastmod>2025-04-28T20:25:58+00:00</lastmod>
+    <lastmod>2025-04-28T20:35:39+00:00</lastmod>
 </url>
 <url>
     <loc>https://www.ioccc.org/status.json</loc>