Create triangular shapes of the same Gems by rotating 3 gems. Click on gems to rotate. You can change the direction of the rotate with the rotate button on the right.
Destroy gems by creating lines of 3 or more gems of the same kind.
You can move the gems by using the mouse to click and swap adjacent gems. ("Adjacent" is when two things are right next to each other!)
Each level is complete when you've made a gem disappear in every spot in the game field.