title: How to multiply two 4x4 matrices, written as two 16-element arrays?
body: <p>I need to have a 4x4 matrix like this:</p>
  
  <pre><code>1  2  3  4
  5  6  7  8
  9  10 11 12
  13 14 15 16
  </code></pre>
  
  <p>represented as an array like this:</p>
  
  <pre><code>[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16]
  </code></pre>
  
  <p>How do I multiply two such "matrices"? I've been struggling with how to make the work for a few days now. I'm thinking this would require three for loops? Maybe two? Would they go to 4 or 16? Some pseudocode would be greatly appreciated :(</p>