The game works by showing you a series of geometries that need to be adjusted a little bit to make them right. A square highlights the point that needs to be moved or adjusted. Use the mouse to drag the blue square or arrowhead where you feel it is 'right'. Once you let go of the mouse, the computer evaluates your move, so don't let up on the mouse button until you are sure. The 'correct' geometry is also shown in green. To avoid the need for extra mouse clicks, a mouse button up counts as the move being finished, so be careful.
You will be presented with each challenge three times. The table to the right shows how you did on each challenge each time.