There's a story about this two-faced baby girl named Lali on CNN right now. Check her out.
http://i.l.cnn.net/cnn/2008/WORLD/asiapcf/04/08/baby.heads.ap/art.LALI.TWO.jpg
Here's some deep thoughts that immediately come to mind:
What would you perceive with two sets of eyes?
If one eye sees in two dimensions, and two eyes see in three dimensions, how many dimensions would you see in with four eyes?
How would you dream?
Think of all the ways you could look at "yourself" in the mirror.
Could a body with two faces be considered conjoined twins, joined at the... everything?
Or in other words... do two faces constitute two personas, even with one human brain?
The answer isn't as simple as "no" because I already tried thinking of it that way.
So many possibilities! Read slowly, cause each of these sentences deserves at least 5 seconds of playful wonderment:
...You could harmonize with yourself.
...You could watch your right AND left hands when you play piano or guitar.
...You could talk in stereo. And smell in stereo.
...You could look both ways before crossing.
...You could suck both of a girl's titties at once.
...You could hold one face underwater for as long as you wanted.
...You could be the happy and sad theater masks for Halloween.
...You could eat in half the time.
...You could watch the professor and take notes without missing a thing.
...You could watch the professor and stare at the hot girl in the soccer shorts without missing a thing.
God it sucks having only one face, when you think about it.