# 4.2. User Interaction

The cursor (a circle) can be moved around the box with the standard cursor movement keys. Switching of lasers or marking of black boxes is done by the left mouse button, or by pressing "Return" or "Enter" keys. You can mark the fields, where a ball can't be, too. Just press the right mouse button. It often helps you to find an area, where a ball could possibly be. To clear any marks (blue or brown) press the left mouse button. Brown marks can't overwrite blue marks. This way you can't erase the blue marks (guessed balls) by accident when playing with the right mouse button.

When you think the configuration of balls you have placed is correct, press the middle mouse button. You will be informed whether you are correct or not, and be given your score. Your score is the number of letters and numbers around the outside of the box plus five for each incorrectly placed ball. If you placed any balls incorrectly, they will be indicated with red fields, and their actual positions indicated with cyan fields.