Concerning my reply to you, Beingsaved, It is not my idea or opinion, I am trying to explain with my words how you could accept (not necessarily understand) the Trinity as God is.
Every analogy, metaphor, comparison (the worst idea for explaining something) can’t render in full something that is not the World. We must get closer and closer to God as it is, but will never be able to “show” Him with words.
So yes, the intersections say something about God, but let also something out. As humans, to define a Tri-Une God, we tend to emphasize the three Persons different from each other (which is true) and by doing this the one Essence escapes us somehow. So then we add the idea that the Essence of God is one, and then…yes we run in circles, as some of the imagery used for the Trinity, the circle being, motion, dynamism, infinity, giving, taking, sharing, eternally.
If one tries to concentrate on the differences of the Persons, maybe, could see why the Spirit is of both Son and father.
Creation: The Spirit of God was there with God (Father and Spirit) and God said (Word)
The Prophets: talk about God the Father thanks to the Spirit of God (H. SP.) and then you see somehow that a divine Son of Man is there with God and is given the power of god.
Then after the Resurrection, once again, Jesus says all the power has been given to me. Since the Son gives live (as the Father does) and the Live is the Spirit of God, then the Son gives the Spirit as his, from the Father in accordance with Him.
As God during the creation of Man, breathes and gives the Spirit, so does Jesus with the Apostles, not saying that the Father gives the Spirit through Him, but that He Jesus gives Him from the Father.