Likewise, the hind parts of Abba and Imma themselves – which descended to the place of Zeir Anpin and Nukva – become rectified as Partzufim… The hind parts of Abba and Imma went down when the vessels broke. In the repair, through the light of Yesod of Imma in Zeir Anpin, the hind parts of Imma become Leah, while the light of Yesod of Abba generates Jacob.
…and supplement Zeir Anpin and Nukva. i.e. in coupling or interaction (זיווג, zivug). The main interaction is between Zeir Anpin and Rachel, but there is Zeir Anpin and Leah, Jacob and Leah and Jacob and Rachel.