Modern Meditational Yoga emphasises the mental techniques of concentration and meditation. Mahamudra has similarities with Dzogchen, emphasizing the meditational approach to insight and liberation. In April 2007, he released "Hudson River Wind Meditations", an album of ambient meditational music. Yidam is sometimes translated by the terms "meditational deity" or "tutelary deity". This is called Thirteen Meditational Contemplations (The Jozengzi). The second root is the meditational deity or yidam. The meditational frescoes in the cells of the convent have a quieting quality about them. The meditational aspects of Shaivism focus on the nirguna form of Supreme Reality (Shiva). This period thus came to be described as "five doctrinal and two meditational schools". They achieve this by attaining advanced meditational levels in another life. This is an extension of the Thirteen Meditational Concentrations. Some of them were created for meditational purpose. However, depending on the meditational tradition, these vary between three and six.