diff --git a/dto.php b/dto.php
index f2ad13f..a94ff80 100644
--- a/dto.php
+++ b/dto.php
@@ -3,16 +3,17 @@
 class User {
     private string $firstName;
     private string $lastName;
-    private string $street;
-    private string $zip;
-    private string $city;
+
+    private Address $invoiceAddress;
+    private Address|null $deliveryAddress = null;
 
     public function __construct(array $data) {
         $this->firstName = $data['firstName'];
         $this->lastName = $data['lastName'];
-        $this->street = $data['street'];
-        $this->zip = $data['zip'];
-        $this->city = $data['city'];
+        $this->invoiceAddress = new Address($data['invoiceAddress']);
+        if (empty($data['deliveryAddress']['street'])) {
+            $this->deliveryAddress = new Address($data['deliveryAddress']);
+        }
     }
 
     public function getFirstName(): string {
@@ -23,6 +24,26 @@ public function getLastName(): string {
         return $this->lastName;
     }
 
+    public function getInvoiceAddress(): Address {
+        return $this->invoiceAddress;
+    }
+
+    public function getDeliveryAddress(): Address {
+        return $this->deliveryAddress ?: $this->invoiceAddress;
+    }
+}
+
+class Address {
+    private string $street;
+    private string $zip;
+    private string $city;
+
+    public function __construct(array $data) {
+        $this->street = $data['street'];
+        $this->zip = $data['zip'];
+        $this->city = $data['city'];
+    }
+
     public function getStreet(): string {
         return $this->street;
     }
diff --git a/index.php b/index.php
index b4ad82b..df51736 100644
--- a/index.php
+++ b/index.php
@@ -1,23 +1,25 @@
 <?php
-require "dto.php";
+require_once "dto.php";
 
 if (empty($_GET['firstName'])) {
 ?>
 <!DOCTYPE html>
 <html lang="en">
-	<head>
-		<title>commit hygiene example</title>
-	</head>
+    <head>
+        <title>commit hygiene example</title>
+    </head>
     <body>
         <form>
-            <label for="firstName">first name</label>
-            <input id="firstName" name="firstName" /><br>
-            <label for="lastName">last name</label><input id="lastName" name="lastName" /><br>
-            <label for="street">street</label>
-            <input id="street" name="street" /><br>
-            <label for="zip">zip</label><input id="zip" name="zip" /><br>
-            <label for="city">city</label>
-            <input id="city" name="city" /><br>
+            <label>first name <input name="firstName"/></label><br>
+            <label>last name <input name="lastName"/></label><br>
+            <h2>invoice address</h2>
+            <label>street <input name="invoiceAddress[street]"/></label><br>
+            <label>zip <input name="invoiceAddress[zip]"/></label><br>
+            <label>city <input name="invoiceAddress[city]"/></label><br>
+            <h2>delivery address (optional)</h2>
+            <label>street <input name="deliveryAddress[street]"/></label><br>
+            <label>zip <input name="deliveryAddress[zip]"/></label><br>
+            <label>city <input name="deliveryAddress[city]"/></label><br>
             <button type="submit">submit</button>
         </form>
     </body>
@@ -25,21 +27,23 @@
 <?php
 } else {
     $user = new User($_GET);
-    ?>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+?>
+<!DOCTYPE html>
 <html lang="en">
-	<head>    <title>commit hygiene example</title> </head>   
+    <head><title>commit hygiene example</title></head>
     <body>
-        <h1><?=$user->getFirstName() . ' ' . $user->getLastName()?></h1>
-        <p><?=$user->getStreet()?><br><span style="font-size: larger"><?=$user->getZip()?></span> <?=$user->getCity()?>
+        <h1><?= htmlspecialchars($user->getFirstName() . ' ' . $user->getLastName(), ENT_HTML5) ?></h1>
+        <h2>invoice address</h2>
+        <p>
+            <?= htmlspecialchars($user->getInvoiceAddress()->getStreet(), ENT_HTML5) ?><br>
+            <span style="font-size: larger"><?= htmlspecialchars($user->getInvoiceAddress()->getZip(), ENT_HTML5) ?></span> <?= htmlspecialchars($user->getInvoiceAddress()->getCity(), ENT_HTML5) ?>
+        </p>
+        <h2>delivery address</h2>
+        <p>
+            <?= htmlspecialchars($user->getDeliveryAddress()->getStreet(), ENT_HTML5) ?><br>
+            <span style="font-size: larger"><?= htmlspecialchars($user->getDeliveryAddress()->getZip(), ENT_HTML5) ?></span> <?= htmlspecialchars($user->getDeliveryAddress()->getCity(), ENT_HTML5) ?>
         </p>
-        <form>
-            <button type="submit" formaction="index.php">new</button>
-        </form>
     </body>
 </html>
 <?php
 }
-?>
-
-
