PHP Taskbook Level 8.2

Given some URL:

php$url = 'http://test.com/dir1/dir2/dir3/page.html';

Get the page name from it:

php'page.html';

Given an array, the subarrays of which contain numbers:

php[
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9],
]

Merge the elements of this array into numbers:

php[123, 456, 789]

Display the following pyramid on the screen: