title: Dynamic maze mutation
body: <p>I have an idea of creating yet another maze game. However, there is a key difference: maze changes on-the-fly during the game. When I think of the problem the following restrictions come into my mind:</p>
  
  <ol>
  <li>there is main route in the maze which never changes</li>
  <li>the main route is the only route which leads to the finish</li>
  <li>maze mutation should not block paths back to the main route</li>
  </ol>
  
  <p>It also would be nice to control (affect game difficulty):</p>
  
  <ol>
  <li>how much of the maze gets changed during a single mutation</li>
  <li>optionally disable restriction #3 (i.e. player can get blocked in the maze for a while)</li>
  </ol>
  
  <p>EDIT:
  The question is: can you suggest an algorithm (or give your ideas) for described maze generation/mutation, which will not violate given restrictions?</p>