Johnny Luken wrote on Mon, Apr 13, 2015 05:11 PM UTC:
Like the swapper, the withdrawer can be extended quite logically.
Allow it to capture pieces in its line of sight as many squares distant or less as it moves when making the capture.
It already does this when capturing adjacent pieces.
In this way, the withdrawer could capture pieces as many as 4 squares distant using the outer edge of the board.