World one hundred and seventy-two have seven boxes in very tiny rooms.
Step by step solution
Go RIGHT, DOWN, push DOWN, DOWN and DOWN. Go UP, UP, UP, UP, UP, UP, RIGHT, UP, RIGHT, RIGHT, DOWN and push LEFT. Push DOWN, DOWN, go RIGHT, DOWN, push LEFT and LEFT.
Go RIGHT, UP, UP, UP, push LEFT, LEFT, go DOWN, DOWN, push DOWN, DOWN, DOWN, go RIGHT, RIGHT, DOWN, DOWN, LEFT and push LEFT. Push UP, UP, UP, UP and UP. Go LEFT, LEFT, LEFT, UP, UP, RIGHT, push RIGHT, RIGHT and RIGHT.
Go UP, RIGHT, push DOWN, DOWN, DOWN, go RIGHT, DOWN, push LEFT and LEFT. Go RIGHT, UP, UP, UP, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, RIGHT, RIGHT, RIGHT, push DOWN, DOWN and DOWN. Go RIGHT, RIGHT, DOWN, DOWN, LEFT, LEFT and push UP. Go LEFT, LEFT, LEFT, LEFT, LEFT, UP, UP, UP, UP, LEFT, UP, push RIGHT, RIGHT, go UP, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, DOWN, DOWN, DOWN, LEFT, LEFT, UP, LEFT, LEFT, LEFT and push UP.
Go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT, push DOWN, DOWN, DOWN, go RIGHT, DOWN, push LEFT and LEFT. Go RIGHT, UP, UP, UP, LEFT, LEFT, LEFT and push DOWN. Go UP, LEFT, LEFT, DOWN, DOWN, RIGHT and push RIGHT. Go LEFT, LEFT, UP, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT and push UP. Go DOWN, LEFT, LEFT, UP, UP, LEFT and push LEFT. Go RIGHT, RIGHT, DOWN, DOWN, LEFT, LEFT, LEFT, UP, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, go UP, RIGHT, RIGHT, RIGHT, DOWN, DOWN, LEFT, LEFT and push UP.
Go LEFT, UP, push RIGHT, RIGHT and RIGHT. Go LEFT, LEFT, LEFT, DOWN, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, DOWN, DOWN, DOWN, DOWN, LEFT and push UP. Go RIGHT, UP, RIGHT, RIGHT, DOWN, push LEFT, LEFT, go UP, UP, UP, LEFT, LEFT, LEFT, DOWN, DOWN, RIGHT, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT and push UP.
Go DOWN, LEFT, LEFT, DOWN, LEFT, push UP, go RIGHT, UP, UP, UP, LEFT, LEFT, LEFT, DOWN, DOWN, RIGHT, push RIGHT, RIGHT and RIGHT.
Congratulations. You have completed world one hundred and seventy-two. Get ready for world one hundred and seventy-three.