You will be given a random number at the start of the game.
There are four crystals below. By clicking on a crystal you
will add a specific amount of points to your total score.
You win the game by matching your total score to the random
number, but you lose the game if your total score exceeds
the random number. The value of each crystal is hidden from
you until you click on it. Each time you start a new game,
the values of each crystal will change.