title: completely erasing UIBezierPath & CAShapeLayer drawn items
body: <p>In portrait mode (first time drawing)</p>
  
  <p><img src="https://i.stack.imgur.com/QNKoG.png" alt="enter image description here"></p>
  
  <p>After rotating to landscape, why are the older shapes:</p>
  
  <p><img src="https://i.stack.imgur.com/OSFhj.png" alt="enter image description here"></p>
  
  <p>I am using <code>UIBezierPath</code> &amp; <code>CAShapeLayer</code> to draw circles &amp; lines in a custom <code>UIView</code>'s layer. The problem is inspite of being able to draw new circles &amp; lines successfully after device is rotated, I  am unable to remove the older drawn shapes. 
  The new shapes drawn after device rotation are perfect, I just need to remove from screen those older shapes sticking in the screen.
  Images attached.</p>