The core of the Yantra is composed of one or several simple geometrical shapes : dots, lines, triangles, squares, circles and lotuses representing in different ways the subtle energies. Every Yantra is delimited from the exterior by a line or a group of lines forming its perimeter. These marginal lines maintain, contain and prevent the loss of the magical forces represented by the core structure of the Yantra, usually the central dot. They also have to increase its magical and subtle force. The core of the Yantra is composed of one or several simple geometrical shapes : dots, lines, triangles, squares, circles and lotuses representing in different ways the subtle energies.