Boomerang Boulders

This is one of the new possible maps for Sokoban Level 1 in Nethack Fourk and Level 2 in Hack'EM. It has 12 boulders and 10 holes, leaving 2 spare boulders.

         ----     0 boulder
 ---------..---   ^ hole
 |.0.0....0...--- > starting position/downstairs
 |.......|0..0..| < upstairs
---------|....0.| + door
|.^^^^^^<|...0..| ? scroll of earth
|.^------|-.-----
--^^^.0..|.0...| 
 |??|0.>....00.| 
 ---|....|.....| 
    ------------ 

Strategy

The following solution may not be very fast or organized. Improvements welcome. Like all Sokoban levels it can be solved without making any boulders 'stick'.

All boulders are replaced by letters so they can be referred to. Letters O and Q are skipped for clarity. Moving the boulders is shortened to r for right, l for left, u for up, d for down. An asterisk is used to denote the last move filled a hole (and thus removed the boulder from the game). So "N ddrr*" means move boulder N two times down and two times to the right into a hole.

         ----     A ll*
 ---------..---   B ull*
 |.L.K....J...--- C uuud ddd
 |.......|I..H..| D u
---------|....G.| C llll llul ll*
|.^^^^^^<|...F..| E llll llll ulll u*
|.^------|-.----- D luuu dddd llll llul lluu*
--^^^.A..|.C...| 
 |..|B.>....DE.| 
 ---|....|.....| 
    ------------ 

         ----     H d
 ---------..---   F lldd dlll lllu lllu ur*
 |.L.K....J...--- H dlld ddll llll ulll uurr*
 |.......|I..H..| G dlll dddl llll lull luur rr*
---------|....G.|
|..^^^^^<|...F..|
|..------|-.-----
--.......|.....| 
 |..|..>.......| 
 ---|....|.....| 
    ------------ 

         ----     J lllr rrrd dddd dlll lllu lllu urrr r*
 ---------..---   I ulll rrrr dddd ddll llll ulll uurr rr*
 |.L.K....J...---
 |.......|I.....|
---------|......|
|.....^^<|......|
|..------|-.-----
--.......|.....| 
 |..|..>.......| 
 ---|....|.....| 
    ------------