The Sri Yantra or Sri Chakra is a form of mystical diagram (yantra) used in the Shri Vidya school of Hindu tantra. It consists of nine interlocking triangles that surround a central point known as a bindu. Because of its nine triangles, Sri Yantra is also known as the Navayoni Chakra. When the two-dimensional Sri Yantra is represented in three dimensions, it is called a Maha Meru. Mount Meru derives its name from this shape. The worship of the Sri Yantra is central to the Shri Vidya system of Hindu worship. It represents the goddess in the form of Shri Lalita or Tripura Sundari, the beauty of the three worlds: Bhu Loka (Physical Plane, Consciousness of the Physical Plane), Bhuvar Loka (Antariksha or Intermediate Space, Consciousness of the Prana) and Swar Loka (Svarga or Heaven or Consciousness of the Divine Mind). The Sri Yantra is the symbol of Hindu tantra, which is based on the Hindu philosophy of Kashmir Shaivism. The Sri Yantra is the object of devotion in Sri Vidya. The Sri Yantra represents the union of Masculine and Feminine Divine. The four upward-pointing isosceles triangles represent the goddess's masculine embodiment Shiva, while the five downward-pointing triangles symbolize the female embodiment Shakti. The Sri Yantra is also known as the nav chakra because it can be seen to consist of nine concentric layers that radiate outward from the bindu. ("Nau" or "nava" means "nine" in Sanskrit.) Each level corresponds to a mudra, a yogini, and a specific form of the deity Tripura Sundari along with her mantra.