title: Validate canvas drawing
body: <p>I made this small drawing <em>app</em> using HTML5 Canvas, where kids can learn how to write letters and numbers. I want to know whether the letter/number has be drawn correctly.</p>
  
  <p>I tried to do something like <a href="http://liveweave.com/k9vRVh" rel="nofollow">this</a> to detect simple straight lines, like number '1'.</p>
  
  <p>But I can't figure out how to detect complex shapes like numbers '2', '8' (well, anything other than straight lines)</p>
  
  <ul>
  <li><a href="http://liveweave.com/MRWoju" rel="nofollow">Number 2</a></li>
  <li><a href="http://liveweave.com/UsxKPw" rel="nofollow">Number 8</a></li>
  </ul>
  
  <p>Help?</p>