2) Then, push up the lower yellow box to a destination point so as to able to push down the bottom box. I think this step is obvious.
3) It is no doubt that we should complete from the bottom boxes first.
4) In order to move box to central line, we should push from the central. Push the center upper box toward left and push down one center box. Just stop before 1 step from the bottom or it will be a dead end.
5) Free up space in order to push up the left lower yellow box.
6) Push up 1 step and you can push up the lower left yellow box, other wise, cannot complete the third lower central box.
7) Clean it up first before you close the lower door.
8) You complete the third bottom box!
9) Move the center box to complete the forth lower central box. And fill in the center with the left yellow box.
10) Complete the lower part, all you need to do is free a space for the upper left one.
11) Complete!
