anchor.diff:    p.
       Add the following code to the bottom of <code>web/main.dart</code>:
   
  -  pre.prettyprint
  -    code.
  -      main() {
  -        // Temporarily needed.
  -        reflector.reflectionCapabilities = new ReflectionCapabilities();
  -
  -        bootstrap(AppComponent);
  -      }
  -
  -  // [PENDING: add line numbers once we can specify where they start]
  +  code-example(language="dart" format="linenums:15").
  +    main() {
  +      reflector.reflectionCapabilities = new ReflectionCapabilities();
  +      bootstrap(AppComponent);
  +    }
   
     p.
       This code adds a <code>main()</code> function
  
positive.code:     Update <code>web/main.dart</code>, adding the following code
      after the imports:
  
    pre.prettyprint
      code.
        @Component(
          selector: 'my-app'
        )
        @View(
          template: '&lt;h1&gt;Hello {{ name }}&lt;/h1&gt;'
        )
        class AppComponent {
          String name = 'Alice';
        }
  
    // [PENDING: add line numbers once we can specify where they start]
  
    p.
      The code you just added creates a component that
      has the tag <b>&lt;my-app></b>.
      The Dart code for an Angular component consists of a class
      (the <b>component controller</b>)
      that has <code>@Component</code> and <code>@View</code> annotations.
  
  
    .l-sub-section
      h3 Annotations
  
      p.
        The <code>@Component</code> annotation defines
        the HTML tag for the component by specifying the component's CSS selector.
  
      p.
        The <code>@View</code> annotation defines the HTML that
        represents the component. This component uses an inline template,
        but you can also have an external template. To use an external template,
        specify a <code>templateUrl</code> property
        and give it the path to the HTML file.
  
      pre.prettyprint
        code.
          @Component(
            selector: 'my-app'
          )
          @View(
            template: '&lt;h1&gt;Hello {{ name }}&lt;/h1&gt;'
          )
  
      // [PENDING: add line numbers once we can specify where they start]
  
      p.
        The annotations above specify an HTML tag of <code>&lt;my-app&gt;</code>
  
negative.code:     Still in the same directory, create a <code>web</code> directory.
      Create a file under <code>web</code> named <code>main.dart</code>.
  
    code-example(language="sh").
      &gt; <span class="blk">mkdir web</span>
      &gt; <span class="blk">vim web/main.dart</span>  # Use your favorite editor!
  
    p.
      Edit <code>web/main.dart</code> to import the angular2 library
      and two reflection libraries:
  
    code-example(language="dart" format="linenums").
      import 'package:angular2/angular2.dart';
      import 'package:angular2/src/reflection/reflection.dart' show reflector;
      import 'package:angular2/src/reflection/reflection_capabilities.dart' show ReflectionCapabilities;
  
  // STEP 3 - Define a component ##########################
  .l-main-section
  