I am not sure if this has already been said but it seems as if the picture on the left is cropped slightly different than the one on the right....
example on the close-up scull ans cards you can see way more of the knife on the right picture than on the left....Do you think this is on purpose??

that what makes the pics 3d they tape two cameras together and take a photo

To ellaborate, it gives the perspective of two eyes. Like when you close one eye, then the other it causes a different perspective, and with only one eye open you lose depth percetion.

The photos work the same way those old view goggles with the cartriges and the little lever thingy.