In this example, the layout file: 
<?php
/**
 * views/layouts/main-layout.php
 *
 * @var $this \Nullai\Vista\Engines\ViewRenderEngine
 */
?>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>My Site</title>
        <?php $this->yield('scripts'); ?>
    </head>

    <body>
        <?php $this->yield('main');  ?>

        <?php $this->include('sidebar', ['menu' => ['Home', 'About', 'Contact']]); ?>

        <?php $this->yield('footer'); ?>
    </body>
</html>
The include('sidebar', ['menu' => ['Home', 'About', 'Contact']]) method passes a menu variable to the sidebar.php view. Inside sidebar.php, the $menu array will be accessible. 
<?php
/**
 * Sidebar view file
 * @var array $menu The array of menu items passed to this view
 * @var $this \Nullai\Vista\Engines\ViewRenderEngine
 */
?>
<aside class="sidebar">
    <nav class="menu">
        <ul>
            <?php foreach ($menu ?? [] as $item): ?>
                <li>
                    <a href="#"><?= htmlspecialchars($item, ENT_QUOTES, 'UTF-8') ?></a>
                </li>
            <?php endforeach; ?>
        </ul>
    </nav>
</aside>

​
Advanced Include Features

Expanding the project to include a users’ folder. 
project-root/
├── vendor/
│   └── autoload.php
├── views/
│   ├── layouts/
│   │   └── main-layout.php
│   ├── users/               # Users folder
│   │   ├── parts/           # Partials folder
│   │   │   └── form.php     # User edit form
│   │   └── index.php        # User index
│   │   └── edit.php         # User edit
│   └── home.php
│   └── sidebar.php
├── public
│   └── index.php

​
Relative Include

To include a view relative to the current view file prefix the include value with :: 
<?php
/**
 * views/users/edit.php
 *
 * @var $this \Nullai\Vista\Engines\ViewRenderEngine
 * @var $content string
 */
$this->layout('layouts.main-layout');

echo $content;
?>

<?php $this->include(':parts/form', ['form' => $form]); ?>

​
Conditional Include

You can also include with includeIf() which will only include the view if conditionals are meet: 
<?php
/**
 * views/users/edit.php
 *
 * @var $this \Nullai\Vista\Engines\ViewRenderEngine
 * @var $content string
 */
$this->layout('layouts.main-layout');

echo $content;
?>

<?php $this->includeIf(!empty($form), ':parts/form', ['form' => $form]); ?>

​
File Include

You can include a specific file using its absolute path: 
<?php
/**
 * views/users/edit.php
 *
 * @var $this \Nullai\Vista\Engines\ViewRenderEngine
 * @var $content string
 */
$this->layout('layouts.main-layout');

echo $content;
?>

<?php $this->include(__DIR__ . '/parts/form.php', ['form' => $form]); ?>