K, the Key, is to be moved to contact L, the Latch, so as to move it totally into the grey area.













1 

3 








2 

8 
9 
10 





K 
→ 
5 



L 
→ 



4 


6 

11 







7 



















The object again is to move K to dislodged L. The "tumblers", the numbered blocks, are only to slide in the direction of their respective lengths.
How might you accomplish this?
Note: the black areas are void space.
(In reply to
Any mistake? (possible spoiler) by pcbouhid)
Yes, I think there is a mistake... you can't move 8 and 9 without moving 6 or 3.
My solution is,
Move 1 left (1 square  void space)
Move 2 left (1 square  void space)
Move 5 up (2 squares  void space left by moving 1 and 2)
Move K right (1 square  space left by moving 5 up)
Move 4 up (1 square)
Move 7 left (2 squares  space left by moving 4 up))
Move 6 left (3 squares  space left by moving 4 and 5)
Move 3 left (1 square  space loft by moving 1)
Move 8 and 9 down (2 squares  space left by moving 6 and 7)
Move K right (2 squares  space left by moving 8 and 9)
Move 10 up (space left by moving 3)
Finally, move K right, so moving the latch L into the grey area.