title: How to parse a string of characters into groups when the characters are in a row column order?
body: <p>I have a string that can be of any length.</p>
  
  <p><code>aaabbbcccdddeeefffggghhhiiijjjkkklllmmmnnnooopppqqqrrrsssttt</code></p>
  
  <p>I want to be able to get all the groups of characters from it.  The number of groups in the string is unlimited.</p>
  
  <p>A group is made up of 3 columns, and 4 rows.  So if I split that string up into groups, it would look like this...</p>
  
  <pre><code>aaa  bbb  ccc  ddd  eee
  fff  ggg  hhh  iii  jjj
  kkk  lll  mmm  nnn  ooo
  ppp  qqq  rrr  sss  ttt
  </code></pre>
  
  <p>So the first group of characters would be...</p>
  
  <p><code>aaa fff kkk ppp</code></p>
  
  <p>Second...</p>
  
  <p><code>bbb ggg lll qqq</code></p>