Philip K. Dick asked "Do Androids Dream of Electric Sheep?"
Asimov's three laws:
1) A robot may not injure a human being or, through inaction, allow a human being to come to harm.
2) A robot must obey orders given to it by human beings, except where such orders would conflict with the First Law.
3) A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
Zeroth Law: A robot may not harm humanity, or, by inaction, allow humanity to come to harm.
Necker Cube:
http://en.wikipedia.org/wiki/Necker_cube