<?php

$topics = [
    [
        'id' => 1,
        'title' => 'Learn PHP the right way!',
        'posts' => [
            ['body' => 'Practice a lot.'],
            ['body' => 'Work on a project.'],
        ]
    ],
    [
        'id' => 2,
        'title' => 'Learn Java the right way!',
        'posts' => [
            ['body' => 'Watch me code.'],
            ['body' => 'Code it as well.'],
        ]
    ],
];

foreach ($topics as $topic) {
    echo $topic['title'] . PHP_EOL;
    foreach ($topic['posts'] as $post) {
        echo "  > " . $post['body'] . PHP_EOL;
    }
    
}