title: slicing to reverse string confusion
body: <p>This has been asked many times but i do not want to ask that again . I just want to know how
  is this happening ?</p>
  
  <pre><code>&gt;&gt;&gt; st="arindam"
  
  &gt;&gt;&gt; st[::-1]   #This is the one that everyone probably uses 
  'madnira' 
  </code></pre>
  
  <p>Would someone please explain why this works?</p>
  
  <pre><code>&gt;&gt;&gt; st[-1::-1]
  'madnira'
  </code></pre>
  
  <p>How is this also reversing the string successfully? I thought this would start from 'a'
  and print 'adnira'</p>