title: Creating merged table cells using Twitter Bootstrap
body: <p>How can we use Bootstrap to create <code>&lt;thead&gt;</code> with 2 levels (eg: Summer Period has hildren data1, data2, data3) and also table cells that merged 2 vertical cells (eg:State)?</p>
  
  <p>Here's how it looks like in Excel:</p>
  
  <p><img src="https://i.stack.imgur.com/d9cMS.jpg" alt="enter image description here"></p>