title: Using excel find all possible combinations in five columns
body: <p>Using Excel, I want to find all possible combinations of 5 letters:</p>
  
  <p>Say, in columns A-E I have the letters: a or A; b or B; c or C; d or D; e or E. </p>
  
  <p>In column F, I want to display each combination. For example:</p>
  
  <pre><code>                       Combinations
  a   b   c   d   e         abcde
  A   B   C   D   E         Abcde
                            aBcde
                            abCde
  </code></pre>