I believe it's been tried at least once, but I have no specific references. There has also been at least one pair of twins conjoined at the head, who can appar

I believe it's been tried at least once, but I have no specific references. There has also been at least one pair of twins conjoined at the head, who can apparently see with each others' eyes (http://www.nytimes.com/2011/05/29/magazine/could-conjoined-twins-share-a-mind.html http://www.nytimes.com/2011/05/29/magazine/could-conjoined-t...). If a human brain learned to see through a ring of eyes, I wonder just how it would adapt to the sensory input.