Vignana Bhairava Tantra - 60

Gaze at an empty mountain

Nirvriksha Giribhithyadi Deshe Drishtim Vinikshipeth|
Vileene Manase Bhave Vrittiksheenah Prajayate||

Cast your eyes in a place where there are mountains or huge rocks, sans trees. As the mind gets dissolved, the different waves of thought or the chitta vrittis get denuded. What the mind sees, that it becomes. Concentration on a barren rock makes the mind similarly singularly focussed. - Swahilya Shambhavi.
(The barren mountains with just a streak of a river flowing between the rocks is situated on the path of the Kailash Parikrama in Tibet. Pic. Swahilya Shambhavi.

Vignana Bhairava Tantra - 59

Empty space in and out
Ghatadi Bhajane Drishtim Bhittees Tyaktwa Vinikshipeth| Tallayam Tatkshanad Gathwa Tallayath Thanmayo Bhaveth|| In this technique of Tantra, Shiva teaches on meditating upon the empty space within the pot. Space is the first creation of the mind and from space the other four elements emerge. Taking a deep look at the space inside the pot, the mind forgets for a moment the presence of the walls of the pot. By focussing on the space, the realisation that everything is just the same space happens. In that moment of merging with empty space, the mind also becomes that oneness which is its essential self. - Swahilya Shambhavi.