Take the right hand, one can put the index finger or the little finger on the root note.
With the index finger on the root, one plays the notes on the right of the root.
With the ring finger on the root (the "Second Position"), one plays the same notes on different keys on the left of the root.
When one plays the major scale, for example, I predict one normally would use both, alternating between them as you go up or down.
The picture to the right is from C-Thru's Coloured Octave map. It shows the slightly canted "axis of unison" well.