Vignana Bhairava Tantra - 46

You are empty within

Tanoodeshe Shoonyataiva Kshanamatram Vibhavayeth
Nirvikalpam Nirvikalpo Nirvikalpaaswaroopabhaat

Now this seems so easy to meditate upon something for just a moment. Consider or imagine, just for a moment, that there is only space inside this body. Imagine just a while that within your outer structure, covered totally by the skin, there is only empty space. This thought leads you to a thoughtless state of mind and you, the contemplating mind becomes that form of void. - Swahilya Shambhavi.

Vignana Bhairava Tantra - 45

Space around and within

Prishtashoonyam Moolashoonyam Hrid Shoonyam Bhavayetsthiram
Yugapad Nirvikalpatwat Nirvikalpodayastataha

By focussing one's awareness on the empty space behind, around and between the thoughts and also realising that in the heart of the thought too, there is nothing but empty space, the mind becomes in tune and merges with the space. In that state of Nirvikalpa, where there are no thought constructions or formations that divert the attention of the mind in one way or the other, there arises the ultimate truth that is always present. - Swahilya Shambhavi.