SPOILERS (Even though that goes without saying i guess)
Quick ending summary:
Disclaimer: My bible knowledge is poor (I hope not to offend anyone):
So my attempts at outside research has led me to a few ideas. Definitely the most powerful symbol in the ending is "Cat's Cradle," or also known as Manger Cradle. This is usually the centerpiece at nativity scenes (and in other words, the reason we celebrate Christmas). I might be thinking too hard about it. The figure Shu makes from Inori's "diamonds" is from what I can tell "Cat's Eye." The big question I am asking myself is: What is the importance of eyes?
It is really easy to see the Adam and Eve connections. The mysterious meteorite that Mana touches represents the "fruit." (there is a scene where you can see her bandaged finger, which was assumed to have touched the stone). But instead of Adam (Shu) taking the fruit offered by Eve (Mana), he refuses it, more than once. Research into the Adam and Eve (Fall of Man) story reveals this:
She then gives the fruit to the man, who eats also, "and the eyes of the two of them were opened." Aware now of their nakedness, they make coverings of fig leaves, and hide from the sight of God.
Which is probably the real explanation behind the sudden blindness of Inori and then of Shu.
Of course, some other things I found interesting was the camera focus on Shu's new robotic arm. This really reminded me of "a pound of flesh," a Shakespearean idiom that references a debt repaid heavily. The fact that he tapped into this "forbidden fruit" (that is the use of voids) means he lost the arm that touched it (his right arm).
But some of the questions that I have lingering are:
1. Where is the Garden of Eden? Is it the white space where Inori and Shu sometimes see each other?
2. Why does Inori live inside Shu? What is the importance of hearing/ears?
I would love to hear what everyone else thinks on this matter.