From a start door, swallow a wooden box and bring it to a hole made by iron boxes on your left.
When you go toward the left, there is a ladder on the edge.
Climb it to the upper floor and then you can find a key.
After you got a key, move to the right.
There is a wooden box on your way and bring it to the far right.
The ladder on the right edge is cracked.
Put a box under the ladder to climb it.
You will find a goal door on the upper left.
Two wooden boxes are needed to go up to the goal door floor.
When you go forward to the left, there is a wooden box beyond a cracked ladder.
Bring it to the lower and make stairs with two boxes to reach a goal door.