There is no letter equivalent for Gar
There is no rune poem for Gar, it is a Northumbrian rune.
Gar as a symbol of the axis mundi, but also of the all, the center and the circumference. Yes, it could be a symbol of Odhinn, but in the sense of him being the Cosmic One, Jormunr, All-father, the one that gave the breath of life, ond. Yet, it is ond that is not yet shaped, not yet apparent, not yet accessible, unlike other runes that reach out to the activating potential. It is the ond of emptiness, of the allness that exists beyond everything, even beyond concepts, that my words fail to express.