within the yogi's body as part of tantric meditations. For example, in the "Yogini Heart" tantra, a Śrī Vidyā text, the yogi is instructed to imagine the five syllables (HA SA KA LA HRIM) of the deity's mantra in the muladhara chakra. The next set of five syllables (HA SA KA HA LA HRIM) is visualized in the heart chakra and the third cluster (SA KA LA HRIM) in the cakra between the eyebrows. The yogi is further instructed to lengthen the enunciation of the M sound at the end of the HRIM syllable, a practice called nada (phonic vibration). This practice goes through various increasingly subtle stages until it dissolves into the silence of the Absolute. Another common element found in tantric yoga is the use of visionary meditations in which tantrikas focus on a vision or image of the deity (or deities), and in some cases imagine themselves as being the deity and their own body as the body of the deity. The practitioner may use visualizations, identifying with a deity to the degree that the aspirant "becomes" the Ishta-deva (or meditational deity). In other meditations, the deities are visualized as being inside the tantrika's body. For example, in Abhinavagupta's Tantraloka (chapter 15), the Trika "trinity" of goddesses (Parā, Parāparā, and Aparā) are visualized on the ends of the three prongs of a trident (located above the head). The rest of the trident is imagined positioned along the central axis of the yogi's body, with the blazing corpse of Shiva visualized in the head. Mandalas and yantras Yantra are mystical diagrams which are used in tantric meditation and ritual. They are usually associated with specific Hindu deities such as Shiva, Shakti, or Kali. Similarly, a puja may involve focusing on a yantra or mandala associated with a deity. According to David Gordon White, geometrical mandalas are a key element of Tantra. They are used to represent numerous tantric ideas and concepts as well as used for meditative focus. Mandalas symbolically communicate the correspondences between the "transcendent-yet-immanent" macrocosm and the microcosm of mundane human experience. The godhead (or principal Buddha) is often depicted at the center of the mandala, while all other beings, including the practitioner, are located at various distances from this center. Mandalas also reflected the medieval feudal system, with the king at its centre. Mandalas and Yantras may be depicted in various ways, on paintings, cloth,