"Over against the border"
The Zohar describes the way in which water, fire, and wind can become unified in our physical existence. Water is the physical expression of the Right Column, the positive energy force of sharing. This male principle [+] corresponds to the proton in an atom. Fire corresponds to the Left Column, the negative energy force of receiving. This female principle [-] is expressed as the electron. Wind is the personification of the Central Column, the neutral energy which corresponds to the neutron in an atom. Just as an atom unites these three forces into the building blocks of our physical universe, we, through our actions, can unite them as the building blocks of our spiritual universe. The positive force relates to the soul and our will to share. The negative force concerns the ego and its bottomless desire to receive and consume.
The neutral force corresponds to the free will of man. Each of us possesses the power to unify these three columns by learning to receive for the sake of sharing, rather than receiving for gratification of the ego.