Bhagavad Gita, Chapter 11, Verse 40

Salutation to You before and behind, salutation to You on every side, O All! You, infinite in power and infinite in prowess, pervade all; wherefore You are All.

Arjun's real bowing spreads out in every direction here, matching a presence that has no single side to face.

Saluting from the front, the back, and all around makes physical sense once this form is understood as filling everything. Real reverence adapts itself to the real shape of what it's honoring.