Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
-----------------
Eidetic Imagery

Eidetic imagery is the ability to retain an accurate visual image of a complex scene or pattern shortly after looking at it. The scene can then be described in detail for a short time. Eidetic imagery is a trait possessed by about 5% of children. The ability to form eidetic images is very rare past adolescence.

To produce an eidetic image, a person must study a scene for some time and must actively concentrate on this scene to retain it in memory. These images fade quickly when the attention is diverted to something else. Naming or identifying parts of the scene tend to interrupt the ability to form an eidetic image. Thus it is very difficult to form an eidetic memory of text.

Sometimes eidetic imagery is called photographic memory. This term is not exactly accurate because this type of memory is not formed like a photograph; eidetic images can be fragmentary and are not necessarily more accurate than normal memories. Additionally, photographic memory is a learned skill rather than a trait you are born with. For example, some people demonstrate impressive memory abilities, with feats like memorizing the number pi [ For more on 'memorizing the number pi' go here: http://www.braingle.com/mind/219.html ] out to thousands of digits. Sometimes these people are described as having photographic memories. In reality, photographic memory is simply the successful application of effective memory techniques. In that respect, photographic memory is a learned skill that you can eventually acquire.
-----------------
For more mind exercises: http://www.braingle.com/mind/