religion Mircea Eliade, the asanas are uncomfortable, typically difficult, cause the body to shake, and are typically unbearable to hold for extended periods of time. However, with repetition and persistence, as the muscle tone improves, the effort reduces and posture improves. According to the Haṭha yoga texts, each posture becomes perfect when the "effort disappears", one no longer thinks about the posture and one's body position, breathes normally in pranayama, and is able to dwell in one's meditation (anantasamapattibhyam). The asanas vary significantly between Haṭha yoga texts, and some of the names are used for different poses. Most of the early asanas are inspired by nature, such as a form of union with symmetric, harmonious flowing shapes of animals, birds or plants. Mudras According to Mallinson, in the earliest formulations, Haṭha yoga was a means to raise and preserve the bindu, believed to be one of the vital energies. The two early Haṭha yoga techniques to achieve this were inverted poses to trap the bindu using gravity, or mudras (yogic seals) to make breath flow into the centre channel and force bindu up. However, in later Haṭha yoga, the Kaula visualization of Kuṇḍalini rising through a system of chakras was overlaid onto the earlier bindu-oriented system. The aim was to access amṛta (the nectar of immortality) situated in the head, which subsequently floods the body, in contradiction with the early Haṭha yoga goal of preserving bindu. The classical sources for the mudras are the Gheranda Samhita and the Hatha Yoga Pradipika. The yoga mudras are diverse in the parts of the body involved and in the procedures required, as in Mula Bandha, Mahamudra, Viparita Karani, Khecarī mudrā, and Vajroli mudra. Meditation The Haṭha Yoga Pradipika text dedicates almost a third of its verses to meditation. Similarly, other major texts of Haṭha yoga such as the Shiva Samhita and the Gheranda Samhita discuss meditation. In all three texts, meditation is the ultimate goal of all the preparatory cleansing, asanas, pranayama and other steps. The aim of this meditation is to realize Nada-Brahman, or the complete absorption and union with the Brahman through inner mystic sound. According to Guy Beck – a professor of Religious Studies known for his studies on Yoga and music, a Hatha yogi in this stage of practice seeks "inner union of physical opposites", into an inner state of samadhi that is described by Haṭha yoga texts in