Problem
Draw a transition diagram for a TM accepting Pal, the language of palindromes over {a, b}, using the following approach. Look at the leftmost symbol of the current string, erase it but remember it, move to the rightmost symbol and see if it matches the one on the left; if so, erase it and go back to the left end of the remaining string. Repeat these steps until either the symbols are exhausted or the two symbols on the ends don't match.