An exercise is a question proposed to the student, who has to provide an answer, be it numerical, textual or graphical.

In a graphical answer exercise, the user must interact with a graphic in order to place the objects in a correct position, that is, in a position in accordance with which is requested as the exercise question.

Because the tool used to interact is the computer mouse (which is very limited), the user must always move single points around the plane (2D) or the space (3D), but the exercise may draw any object using these moving points (such as the triangle in the example in Graphical Laboratory section).