Fly on the Wall

This is one of the new possible maps for Sokoban Level 2 in Nethack Fourk and Level 3 in Hack'EM. It has 17 boulders of which 16 boulders are usable and 15 holes, leaving 1 spare boulder.

                     ----  0 boulder
   -------------------..|  ^ hole
----........^^^^^^^^^^^^-- > starting position/downstairs
|......--00.----------.^.| < upstairs
|.0.--..0..--        |..^| + door
|0.0--00.0.|         --|^|
|.00..0....--  --------|+|
|......0...>|  |.........|
--0----------  |.........|
 |..|          |....<....|
--..-------    |.........|
|.0.0.0...|    |.........|
|.........|    -----------
-----------

Strategy

                     ----  A ulll llrr rrrr r
   -------------------..|  B ulll lrrr rrrr r
----........^^^^^^^^^^^^-- C uuul lllr rrrr rrrr
|......--BA.----------.^.| D rruu rrrr r
|.I.--..D..--        |..^| E urrr uurr rrrr
|J.K--FE.C.|         --|^|
|.LM..G....--  --------|+|
|......H...>|  |.........|
--N----------  |.........|
 |..|          |....<....|
--..-------    |.........|
|.O.P.Q...|    |.........|
|.........|    -----------
-----------

                     ----  J d
   -------------------..|  I urrr rurr rrrr rrrr r
----.............^^^^^^^-- G l
|......--...----------.^.| F uuur rrrr rrrr rrr
|.I.--.....--        |..^| G ruuu urrr rrrr rrrr rr
|J.K--F....|         --|^|
|.LM..G....--  --------|+|
|......H...>|  |.........|
--N----------  |.........|
 |..|          |....<....|
--..-------    |.........|
|.O.P.Q...|    |.........|
|.........|    -----------
-----------

                     ----  L uuur rrru rrrr rrrr rrrr rr
   -------------------..|  M luuu rrrr urrr rrrr rrrr rrrr
----................^^^^-- K uurr rrur rrrr rrrr rrrr rrr
|......--...----------.^.| N dd
|...--.....--        |..^| Q r
|..K--.....|         --|^| P r
|JLM.......--  --------|+|
|......H...>|  |.........|
--N----------  |.........|
 |..|          |....<....|
--..-------    |.........|
|.O.P.Q...|    |.........|
|.........|    -----------
-----------
                     ----  O r
   -------------------..|  N uuuu uuur rrru rrrr rrrr rrrr rrrr r
----...................^-- O luuu uuuu urrr rurr rrrr rrrr rrrr rrrd
|......--...----------.^.| P lllu uuuu uuur rrru rrrr rrrr rrrr rrrr rddr
|...--.....--        |..^| Q llll luuu uuuu urrr rurr rrrr rrrr rrrr rrrd drd
|...--.....|         --|^|
|J.........--  --------|+|
|......H...>|  |.........|
--.----------  |.........|
 |..|          |....<....|
--N.-------    |.........|
|.O..P.Q..|    |.........|
|.........|    -----------
-----------