Hint 1
Once you get a block in the tunnel below the rightmost button, there is no way to get it back.
Hint 2
If you use the steel block to put boxes on all three of the leftmost buttons, you won't be able to retrieve it without messing up the positions of the boxes.
Hint 3
As seen with walls, the force of a push propagates through objects even when they can't move. Is there a way to exploit this using blocks?
