title: Simple nth1 predicate in Prolog
body: <p>With SWI Prolog, there's a predicate that finds the nth item in a list called nth1.  I want to implement my own version of the predicate but SWI's is so complicated if you look at the listing(nth1) code.  Is there a simpler way of doing it?</p>
  
  <p>Thank you :).</p>