;  c. 2006 Jeff Rayhorn & LukewarmCoffee.com
(defun swap ()
(setvar "cmdecho" 0)
(command "undo" "be")
(prompt "\nSelect first group of objects, [ENTER] when done...")
(setq frstset(ssget))
(setq frstpnt(getpoint "\nPick base point for the first group of objects..."))
(prompt "\nSelect second group of objects, [ENTER] when done...")
(setq scndset(ssget))
(setq scndpnt(getpoint "\nPick base point for the second group of objects..."))
(command "move" frstset "" frstpnt scndpnt)
(command "move" scndset "" scndpnt frstpnt)
(command "undo" "e")
(princ)
)