There are three stone keys given in the game.  You will find
difficulties matching those stone keys because it is 
neccessary to match those stone keys to go to next puzzle.  
However there is easier way to solve that problem than 
trying all the possibilities.  It won't be hard to get the
first stone in the right place.  All you have to do is just
to remember the placement of the first stone.  When you get
to the two stone key problem, the first stone will be placed
where it was before in first place.  It is same for the 
second and third stones.