diff -u b/fapi_example/src/Form/BuildDemo.php b/fapi_example/src/Form/BuildDemo.php
--- b/fapi_example/src/Form/BuildDemo.php
+++ b/fapi_example/src/Form/BuildDemo.php
@@ -32,7 +32,7 @@
    * {@inheritdoc}
    */
   public function __construct() {
-    $this->displayMethodInvocation('__contstruct');
+    $this->displayMethodInvocation('__construct');
   }
 
   /**
@@ -40,7 +40,7 @@
    * processing.
    *
    * @param $method_name
-   *   The method being invoked. 
+   *   The method being invoked.
    */
   private function displayMethodInvocation($method_name) {
     self::$_sequence++;
diff -u b/fapi_example/src/Form/ContainerDemo.php b/fapi_example/src/Form/ContainerDemo.php
--- b/fapi_example/src/Form/ContainerDemo.php
+++ b/fapi_example/src/Form/ContainerDemo.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Form\FormStateInterface;
 
-
 /**
  * Implements the container demo form.
  *
@@ -20,13 +19,11 @@
 class ContainerDemo extends DemoBase {
 
   /**
-   * Build the simple form.
-   *
-   * @inheritdoc
+   * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
 
-    // Details containers replace collapsible field sets in D7.
+    // Details containers replace D7's collapsible field sets.
     $form['author'] = [
         '#type' => 'details',
         '#title' => 'Author Info (type = details)',
@@ -39,7 +36,7 @@
 
     $form['author']['pen_name'] = [
       '#type' => 'textfield',
-      '#title' => $this->t('Pen Name')
+      '#title' => $this->t('Pen Name'),
     ];
 
     // Conventional field set.
@@ -58,7 +55,7 @@
       '#title' => $this->t('Publisher'),
     ];
 
-    // Containers have no visual display but wrap any contained elements int a
+    // Containers have no visual display but wrap any contained elements in a
     // div tag.
     $form['accommodation'] = [
       '#type' => 'container',
@@ -70,14 +67,13 @@
       '#value' => $this->t('Special Accommodations (type = container)'),
     ];
 
-    $form['accommodation'] ['diet'] = [
+    $form['accommodation']['diet'] = [
       '#type' => 'textfield',
       '#title' => $this->t('Dietary Restrictions'),
     ];
 
-    // Convational submit button.
     $form['actions'] = ['#type' => 'actions'];
-    // Add a submit button that handles the submission of the form.
+    
     $form['actions']['submit'] = [
       '#type' => 'submit',
       '#value' => $this->t('Submit'),
@@ -90,10 +86,7 @@
-   * Getter method for Form ID.
-   *
    * @inheritdoc
    */
   public function getFormId() {
     return 'fapi_example_container_demo';
   }
 
-
-}
+}
\ No newline at end of file
diff -u b/fapi_example/src/Form/DemoBase.php b/fapi_example/src/Form/DemoBase.php
--- b/fapi_example/src/Form/DemoBase.php
+++ b/fapi_example/src/Form/DemoBase.php
@@ -7,25 +7,22 @@
 
 namespace Drupal\fapi_example\Form;
 
-
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Form\FormStateInterface;
 
 /**
  * Implements common submit handler used in fapi_example demo forms.
  *
- * This extends FormBase which is the simplest form base class used in Drupal.
- * The class is primarily used to provide a common SubmitForm method for other
- * form controllers to use.
+ * We extend FormBase, which is the simplest form base class used in Drupal, to
+ * add a common submitForm method that will display the submitted values via
+ * drupal_set_message().
  *
  * @see \Drupal\Core\Form\FormBase
- * @see \Drupal\Core\Form\ConfigFormBase
  */
 abstract class DemoBase extends FormBase {
   /**
    * Implements a form submit handler.
    *
-   *
    * @param array $form
    *   The render array of the currently built form.
    * @param FormStateInterface $form_state
@@ -36,7 +33,6 @@
     $values = $form_state->getValues();
     foreach($values  as $key => $value) {
       $label = isset($form[$key]['#title']) ? $form[$key]['#title'] : $key;
-
       // many arrays return 0 for unselected values so lets filter that out.
       if (is_array($value)) $value = array_filter($value);
 
diff -u b/fapi_example/src/Form/SimpleForm.php b/fapi_example/src/Form/SimpleForm.php
--- b/fapi_example/src/Form/SimpleForm.php
+++ b/fapi_example/src/Form/SimpleForm.php
@@ -47,7 +47,7 @@
 
     // Group submit handlers in an actions element with a key of "actions" so
     // that it gets styled correctly, and so that other modules may add actions
-    // to the form.
+    // to the form. This is not required, but is convention.
     $form['actions'] = [
       '#type' => 'actions',
     ];
diff -u b/fapi_example/src/Tests/BuildDemoTest.php b/fapi_example/src/Tests/BuildDemoTest.php
--- b/fapi_example/src/Tests/BuildDemoTest.php
+++ b/fapi_example/src/Tests/BuildDemoTest.php
@@ -47,16 +47,17 @@
 
     // Verify that anonymous can access the page.
     $this->drupalGet('examples/fapi_example/build_demo');
-    $this->assertResponse(200, 'The Demo of Modal Form is available.');
+    $this->assertResponse(200, 'The Build Demoq Form is available.');
 
     // Post the form.
     $edit = [
       'change' => '1',
     ];
     $this->drupalPostForm('/examples/fapi_example/build_demo', $edit, t('Submit'));
-    $this->assertText('getFormId 1');
-    $this->assertText('validateForm 1');
-    $this->assertText('submitForm 1');
+    $this->assertText('1. __construct');
+    $this->assertText('2. getFormId');
+    $this->assertText('3. validateForm');
+    $this->assertText('4. submitForm');
   }
 
 }