Stage four is easier than the third. Here the player is introduced for first time to the IceBox.
Step by step solution
From the initial position, go DOWN once, then RIGHT, RIGHT,
UP and UP.
Push the box to the LEFT once.
You will notice that the box have slided away to the end of the room, straight to the socket. Push DOWN.
Go to LEFT once, then go DOWN.
Push the box to its socket to the RIGHT.
Congratulations. You have completed the fourth World. Get ready for the fifth.