Its centre is a sphere which represents the seed or germ of the universe in its undifferentiated form as ‘bindu’. Its potential force is indicated in pictorial representations by a spiral issuing from the centre of the sphere.
Govinda provides the most detailed structural and cosmological analysis of the vajra sceptre, reading its form — bindu centre, polar lotuses, and spatial quadrants — as a symbolic map of enlightened consciousness unfolding from undifferentiated unity.
, Foundations of Tibetan Mysticism, 1960thesis