The conceptually bridging and building poetic device of analogy, as an exemplar where "dharmakaya" is evocatively likened to sky and space, is a persistent and pervasive visual metaphor throughout the early Dzogchen and Nyingma literature and functions as a linkage and conduit between the 'conceptual' and 'conceivable' and the 'ineffable' and 'inconceivable' (Sanskrit: "acintya"). It is particularly referred to by the "terma" "Gongpa Zangtel" , a terma cycle revealed by Rigdzin Gödem (1337–1408) and part of the Nyingma "Northern Treasures" ().