T. is the instrument for using all the other figures of this Art which revolve around it and since no useful work can be done with the other figures without this one, this book first deals with T. as an instrument. Since this is the very first figure to know in this Art, it is called the first figure, divided into three parts: sensitive, imaginary and intellectual.

The sensitive figure shown on page one is divided into two figures, the first is made of five triangles of different colors, the second consists of three revolving circles each containing all the angles of T. This figure can be made of electrum, metal, paper or any suitable material so the circles can turn to form any camera of T. by combining the triangles to investigate any particular in its universal. Figure T. is always used beside each figure namely figure A., S., V., X., etc. Each angle of the triangles of this figure has twelve propositions and eight questions in accordance with the natural properties of the angle.

The imaginary figure is formed as the imaginative power receives the disposition of the triangles and gathers a universal representation of them to be offered to the intellect.

The intellectual figure is formed as the intellect surveys the sensitive and imaginary figures and forms within itself a universal representation of the totality of T. with all its statements and questions knowing that figure T. is made of universal principles to which the principles of all other figures are reduced.