You can create the illusion of things sticking out of a screen and if the screen is big enough the illusion is easier to maintain. For a "low tech" example of

You can create the illusion of things sticking out of a screen and if the screen is big enough the illusion is easier to maintain. For a "low tech" example of such effects take a look at http://amasci.com/amateur/holohint.html http://amasci.com/amateur/holohint.html and related content.