The Hidden Image: What is it called?

Question

I dont remember exactly what this kind of picture is called....

Its picture of a random background (like the one we recieive from our bank wherein our pin code is written). Once we keep on staring at the picture for some time, perhaps from a special angle, another picture within this picture is revealed. This hidden image isnt obvious just by looking at this background but once we stare for some time, this hidden image becomes apparent.........

Whats this picture called??????! I totally forgot! If anyone can tell me what this is............ I'l ve really greatful!!1

Answer 1

Stereogram Image:

http://good-times.webshots.com/album/557...

There are also hologram inages.

Ron