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 random
number, you lose the game if your total score goes above
the random number.
The values of each crystal is hidden from you until you
click on it.
Each time when the game starts, the game will change the
value of each crystal.