Through the Cracks

This is one of the new possible maps for Sokoban Level 3 in NetHack Fourk and Level 2 in Hack'EM. It has 18 boulders and 15 holes, leaving 3 spare boulders.

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

Strategy

 --------------------- A l
--....||...........+.| E l
|..QR.||...........|^| D d
|.P...||..<........|^| F ll
|.O..--|...........|^| G drrr r
---N-- |...........|^| A lddd rr
 |..---------------|^| C lddr rr
 |...K...H....E..B.|^| F dddr rrrr rr
 |..L...I.-..F..A..|^| H l
--.---..---..-.C.>.|^| I ll
|.M--.J---.G--D-----^| J drrr rrrr rrrr rr
|.............^^^^^^.|
-------------------..|
                  ----

 --------------------- I dddr rrrr rrrr rrrr ru
--....||...........+.| L l
|..QR.||...........|^| M drrr rrrr rrrr rrrr rrru u
|.P...||..<........|^| L lldd drrr rrrr rrrr rrrr rrru uu
|.O..--|...........|^| K llld dddr rrrr rrrr rrrr rrrr ruuu u
---N-- |...........|^| H llll lldd ddrr rrrr rrrr rrrr rrrr uuuu u
 |..---------------|^| E llll llll llld dddr rrrr rrrr rrrr rrrr ruuu uuu
 |...K..H.....E..B.|^| B llll llll llll llld dddr rrrr rrrr rrrr rrrr ruuu uuuu
 |..L.I...-........|^|
--.---..---..-...>.|^|
|.M--..---..--.-----^|
|....................|
-------------------..|
                  ----

 --------------------- N uu
--....||...........+.| R d
|..QR.||...........|^| Q r
|.P...||..<........|^| N dddd dldd drrr rrrr rrrr rrrr rrru uuuu uuu
|.O..--|...........|.| P rddd ddld ddrr rrrr rrrr rrrr rrrr uuuu uuuu u
---N-- |...........|.|
 |..---------------|.|
 |.................|.|
 |........-........|.|
--.---..---..-...>.|.|
|..--..---..--.-----.|
|....................|
-------------------..|
                  ----