Creation, preservation, destruction
Brahma, Vishnu, Shiva
Past, present, future
Father, mother, child
Heaven, earth, underworld
Time, space, consciousness
Sat, chit, ananda (being, consciousness, bliss)
A U M, the three sounds of the primordial syllable
Sattva, rajas, tamas, (the light, the active, the dark), the gunas, or basic pricinples that permeate all