split//,'019617511192'.
      '17011111610114101114'.
      '21011141011840799901'.
            '17101174';
            foreach(0..      
            $#_){$_[$_      
            ++]^=$_[$_          
            --]^=$_[$_
]^=$_[++    $_]if!($_%
2)}$g.=$_  ,chr($g)=~
 /(\w)/&&($o.=$1and
   $g='')foreach@_;
      print"$o\n"
[download]

Not very complicated, but it's the nicest one I've ever done