Block

Blocks are none, one or more instructions, grouped together with or without curly brackets.

Blocks may require brackets, like for classes, switch(), function bodies; they might be optional, like with cases, arrow-functions or loops.

<?php

function foo($a) {
     if ($a) {
             $b = 1;
     } else
             $b = 2;

     return $b;
}
?>