title: Rotating a 5D array in the last 2 dimensions
body: <p>I have a 5D array 'a', of size (3,2,2,2,2).</p>
  
  <pre><code>import numpy as np
  a = np.arange(48).reshape(3,2,2,2,2)
  a[0,0,0]:
  array([[0, 1],
         [2, 3]])
  </code></pre>
  
  <p>What I want to do is rotate this 5D array by 180 degrees, but only in the last two dimensions, without their positions changed. So output[0,0,0] should look like this:</p>
  
  <pre><code>out[0,0,0]:
  array([[3, 2],
         [1, 0]])
  </code></pre>
  
  <p>What I have tried:</p>
  
  <pre><code>out = np.rot90(a, 2)
  out[0,0,0]:
  array([[40, 41],
         [42, 43]])
  </code></pre>
  
  <p>The <code>rot90</code> function apparently rotates the whole array.</p>
  
  <p>Note: I want to avoid using for loops if possible</p>