(defun outline-move-subtree-down (&optional arg)
  "Move the current subtree down past ARG headlines of the same level."
  (interactive "p")
  (let ((movfunc (if (> arg 0) 'outline-get-next-sibling
		   'outline-get-last-sibling))
	(ins-point (make-marker))
	(cnt (abs arg))
	;; Make sure we can move forward to find the end of the
	;; subtree and the insertion point.
	(maybe-forward-char (lambda ()
			      (if (eq (char-after) ?\n) (forward-char 1)
				(if (and (eobp) (not (bolp))) (insert "\n")))))
	beg end folded)
    ;; Select the tree.
    (outline-back-to-heading)
    (setq beg (point))
    (save-match-data
      (save-excursion (outline-end-of-heading)
		      (setq folded (outline-invisible-p)))
      (outline-end-of-subtree))
    (funcall maybe-forward-char)
    (setq end (point))
    ;; Find insertion point, with error handling.
    (goto-char beg)
    (while (> cnt 0)
      (or (funcall movfunc)
	  (unless (or (bobp) (eobp))
	    (goto-char beg)
	    (user-error "Cannot move past superior level")))
      (setq cnt (1- cnt)))
    (if (> arg 0)
	;; Moving forward - still need to move over subtree.
	(progn (outline-end-of-subtree)
	       (funcall maybe-forward-char)))
    (move-marker ins-point (point))
    (insert (delete-and-extract-region beg end))
    (goto-char ins-point)
    (if folded (hide-subtree))
    (move-marker ins-point nil)))