title: Separate individual pdf pages from 2x2 format to 1x1 format
body: <p>My teacher gives us his lectures as a PDF file with a 2 by 2 format. I.e. on one pdf page, there are 4 slides of the presentation (see sketch below).</p>
  
  <p>Does anyone know how to separate each individual pdf page of a multi-page pdf document into 4 pages? I am not looking for coding advice, but rather for a tool that does this for me.</p>
  
  <p>The current page format is like this:</p>
  
  <pre><code>    +-----------+
      |  1  |  2  |
      -------------
      |  3  |  4  |
      +-----------+
  </code></pre>
  
  <p>Thank you for the help!</p>