The Yantra should be made with great precision and should be free of errors or else it will not work. The Yantra is made up of five inverted triangles and has a central point in the middle that resembles a bindu. The triangles in turn are enclosed by three circles and eight petals which in turn are enclosed by four doors. This symbol of the Mahakali Yantra is made on silver or copper plates and can be worn around the neck or arm. Outside the lotus petals is inscribed the "Beej" or seed mantra of the goddess. The Yantra should be made with great precision and should be free of errors or else it will not work. The Yantra is made up of five inverted triangles and has a central point in the middle that resembles a bindu. The triangles in turn are enclosed by three circles and eight petals which in turn are enclosed by four doors.