(define get-maze
'(
(w w w w w w w w w)
(w 3 0 w 0 0 0 0 w)
(w w 0 w 0 w w 0 w)
(w 0 1 0 0 0 0 8 w)
(w w 0 0 0 w w 0 w)
(w 0 5 0 w 0 1 0 w)
(w 4 w 0 w 1 7 0 w)
(w w w w w w w w w)
)
)

(define program
  '(
    (procedure add-mark-to-maze
      (if mark?
       (get-mark
        (if mark?
          (put-mark)
          ( put-mark put-mark
            (if wall? () (step add-mark-to-maze step-back))
            turn-left
            (if wall? () (step add-mark-to-maze step-back))
            turn-left
            (if wall? () (step add-mark-to-maze step-back))
            turn-left
            turn-left
            (if wall? () (step add-mark-to-maze step-back))
            turn-left
            (if wall? () (step add-mark-to-maze step-back))
            turn-left get-mark
          ))
       ) (put-mark add-mark-to-maze get-mark)
     ))
    (procedure step-back
      (turn-left turn-left turn-left step turn-left turn-left turn-left)
    )
    )
)
(newline)
(simulate (list get-maze (list 4 1) 'west) 'add-mark-to-maze program 20)