The Holy Spirit depicted as a dove in the stained glass window behind the Cathedra Petri in St. Peter's Basilica, Rome.
Again, the Trinity was explained:
God the Father represents Isvara God the Holy Spirit represents Atman God the Son represents Guru Isvaro gururatmeti murti bheda vibhagine vyomavad vyapta dehaya dakshinamurtaye namah:
Meaning that God appears to his devotee in the form of a Guru (son of God) and points out to him the immanence of the Holy Spirit. That is to say that God is spirit, that this spirit is immanent everywhere and that the Self must be realised, which is the same as realising God.
Talk 89 Talk 91