title: SML - Concatenating strings in a list within a list
body: <p>So I've got this list of lists of strings:</p>
  
  <pre><code>[["#@","**","#@"],["##","*%","##"]]
  </code></pre>
  
  <p>What I want to do is transform each inner list into a single string like this:</p>
  
  <pre><code>["#@**#@","##*%##"]
  </code></pre>
  
  <p>Resulting in a list of strings. </p>
  
  <p>I've tried various combinations of map, foldr, and anonymous functions, but I can't for the life of me figure out how to achieve my desired result.</p>