diff --git a/README.md b/README.md
index c7e8615..e838e49 100644
--- a/README.md
+++ b/README.md
@@ -12,29 +12,34 @@ The library you need is `graph-diagram.js`. It depends on D3, so you'll need tha
 
 Markup looks like this, enclosed in a `<figure>` tag:
 
-    <figure class="graph-diagram">
-      <ul class="graph-diagram-markup">
-        <li class="node" data-node-id="0" data-x="0" data-y="0">
-          <span class="caption">A</span>
-        </li>
-        <li class="node" data-node-id="1" data-x="50" data-y="0">
-          <span class="caption">B</span>
-        </li>
-        <li class="relationship" data-from="0" data-to="1">
-          <span class="type">R</span>
-        </li>
-      </ul>
-    </figure>
+```html
+<figure class="graph-diagram">
+  <ul class="graph-diagram-markup">
+    <li class="node" data-node-id="0" data-x="0" data-y="0">
+      <span class="caption">A</span>
+    </li>
+    <li class="node" data-node-id="1" data-x="50" data-y="0">
+      <span class="caption">B</span>
+    </li>
+    <li class="relationship" data-from="0" data-to="1">
+      <span class="type">R</span>
+    </li>
+  </ul>
+</figure>
+```
+
 
 See [tests.html](http://www.apcjones.com/arrows/tests.html) for examples of what you can do 
 with markup and styling.
 
 At the end of your page, or in a suitable event handler, call a bit of framework code:
 
-    <script type="text/javascript">
-      d3.selectAll( "figure.graph-diagram" )
-              .call( gd.figure() );
-    </script>
+```html
+<script type="text/javascript">
+  d3.selectAll( "figure.graph-diagram" )
+          .call( gd.figure() );
+</script>
+```
 
 There's also a complete working example in [example.html](http://www.apcjones.com/arrows/example.html).
 
@@ -49,4 +54,4 @@ This whole repository is hosted by GitHub Pages, so you'll find the editor hoste
 
 Yes, lots. Consider the current version experimental at best. 
 There hasn't been any work on browser compatibility, 
-so I'd be surprised if it works properly outside WebKit.
\ No newline at end of file
+so I'd be surprised if it works properly outside WebKit.