Pop Up (crazy idea) - stereo photo

Ah yes, after the animals pop up, I thought to realize this little card, ah I know I'm a nutter ahah
hope you like it! 
For who doesn't know the mean of 2 pics in one...that's an photographic technique called "stereo photography", which if you cross your eyes, the image will become in 3D. If you want to know more, I suggest you the site of the London Stereoscopic Society, which really describes everything in all the minus details -> (www.londonstereo.com)