title: PHP reference variable, Why is $a = 21?
body: <p>Can someone explain to me in a simple language why $a = 21 in the final output?</p>
  
  <pre><code>$a = '1';    
  echo $a . "&lt;br&gt;"; // result 1
  
  $b = &amp;$a;
  echo $b . "&lt;br&gt;"; // result 1
  
  $b = "2$b";
  echo $b . "&lt;br&gt;"; // result 21
  
  echo $a . "&lt;br&gt;"; // result 21 WHY?
  
  echo $a . ", " . $b; // result 21, 21
  </code></pre>
  
  <p>Thank you. I appreciate the help very much.</p>