title: How to merge 2 numpy arrays?
body: <p>I feel like there is some documentation I am missing, but I can't find anything on this specific example - everything is just about concatenating or stacking arrays. </p>
  
  <p>I have array x and array y both of shape (2,3)</p>
  
  <p>x = [[1,2,3],[4,5,6]]</p>
  
  <p>y = [[7,8,9],[10,11,12]]</p>
  
  <pre><code>x = 1 2 3
      4 5 6
  
  y = 7 8 9
      10 11 12
  </code></pre>
  
  <p>I want array z with shape (2,3,2) that looks like this</p>
  
  <p>z = [[[1,7],[2,8],[3,9]],[[4,10],[5,11],[6,12]]]</p>
  
  <pre><code>z = [1,7] [2,8] [3,9]
      [4 10] [5 11] [6 12]
  </code></pre>
  
  <p>basically joins the x and y element at each position. </p>