The concept ‘metaxu’ or ‘between’ is not a geometrical figure. We say ‘between finitude and the infinite,’ for example, as if they are to be classed together. There’s an asymmetry to be dealt with however beyond us such dealing may be.
Heaney’s poetry is full of such evanescent betweens, especially the late poetry. ‘A birch tree planted twenty years ago / Comes between the Irish Sea and me’ (‘In the Attic,’ from HUMAN CHAIN.)
That is, thinking the between requires finesse.