Itching

[PBI]

I read an interesting article on vision a few years ago which this piece reminded me of; apparently, almost all of the colour receptors in the retina are concentrated directly behind the pupil, in a relatively small area. This means that your peripheral vision is essentially black and white; your brain simply "fills in" the missing colours from memory, or if it can't, it guesses (and quite often gets it wrong).

Edit: Oh, I forgot to mention, that article made me itch like crazy. Thanks a bunch, Lemur.