title: Getting pair-set using LINQ
body: <p>When i have a list </p>
  
  <pre><code>IList&lt;int&gt; list = new List&lt;int&gt;();
  list.Add(100);
  list.Add(200);
  list.Add(300);
  list.Add(400);
  list.Add(500);
  </code></pre>
  
  <p>What is the way to extract a pairs </p>
  
  <pre><code>Example : List elements {100,200,300,400,500}
  
  Expected Pair : { {100,200} ,{200,300} ,{300,400} ,{400,500} }
  </code></pre>