Thanks much Marinus. How dumb of me...hard to believe I've made it this far in the game, huh???

There is a total of 5 steel boxes. I've placed the 3 boulders and 3 of the steel boxes over the six buttons to turn off gates. I BELIEVE I now need 4 steel boxes to go over the lava and exit. Have used the 2 free boxes but now must remove 2 boxes that are covering buttons. I have to approach them fr...