Such a sacred symbol may be ritually sought as a focus for meditation, or it may mysteriously obtrude on the attention. Twenty sparrows a day might cross the path of one's vision and never be particularly noticed, yet one still half-alive brought in by the cat, or flying into the house, or just drawing attention to itself in some way, especially loud cheeping in the morning perhaps, may suddenly cause a recollection that the bird is sacred to Aphrodite, Froth-of-Replication, and may be understood as some sort of message from Her.
The Hindustan Vahana (vehicle, or bearer), usually a bird or animal, is the duplicate presentation of the energy and character of the deity it is associated with, who are often portrayed riding the creature in question.
For the Japanese, the shintai is neither a symbol nor the attibute of a deity, but a definite object into which an invisible deity can incorporate erimself in order to establish contact with eris believers. The shintai into which the august soul of the Sun, Amaterasu-Omikami, Great-Heaavenly-Shining-One, may enter to be present at ceremonies, or to come and hear the prayers addressed to Her, is the octagonal mirror (yata kayami).
The exact reasons for the identification between symbol and deity are often obscure, and sometimes quite different between one people and another, yet there is a sort of consistency. It may even be the kind of observant consistency which eventually led to the human ability to classilty the world into types of things.
It's likely I began working on the symbol dictionary at least as early as September 1987.