Sokoban Free

Sokoban 「倉庫番」 (warehouse keeper?) is a type of transport puzzle, in which the player pushes boxes or crates around in a warehouse, trying to get them to storage locations. The puzzle is usually implemented as a video game.
Sokoban was created in 1981 by Hiroyuki Imabayashi, and published in 1982 by Thinking Rabbit, a software house based in Takarazuka, Japan.

Rules
1.Only one box can be pushed at a time.
2.A box cannot be pulled.
3.The player cannot walk through boxes or walls.
4.The puzzle is solved when all boxes are located at storage locations.