title: A Push Down Automata that produces the flip and reverse of a string
body: <p>The alphabet: 0, 1</p>
  
  <p>Consider a flip, to flip each character: 0 -> 1; 1 -> 0
  So if w = 0011 then w-flip = 1100</p>
  
  <p>Consider a reverse to be the characters in reversed order
  So if w = 01101 then w-reverse = 10110</p>
  
  <p>Now I am trying to produce a PDA which takes the string w, and then prints w, prints (w-flip-reversed)</p>
  
  <pre><code>w = 011
  w-flip = 100
  w-flip-reverse = 001
  </code></pre>
  
  <p>So this would print: "011001"</p>
  
  <p>Consider # to be a blank character. So a string would start #011#</p>
  
  <p>Transition table looks something like this:</p>
  
  <pre><code>State:    Symbol Read:    Next State:    Head Instruction:
  start     #               r1             L
  </code></pre>
  
  <p>And so on</p>
  
  <p>Any ideas?</p>