Re: sudoku.el -- puzzle game, can download puzzles on the fly.

[lg]

For (S)XEmacsen sudokuers here is `undo-copy-list' grabbed from
http://www.emacswiki.org/cgi-bin/wiki/selective-undo-xmas.el:

    (defun undo-copy-list (list)
      "Make a copy of undo list LIST. "
      (mapcar 'undo-copy-list-1 list))

    (defun undo-copy-list-1 (elt)
      (if (consp elt)
          (cons (car elt) (undo-copy-list-1 (cdr elt)))
        elt))