Color Blindness
With red/green color blindness, this image:
would look like this:
or this:
or this:
and the interesting thing is that we can't really say which of those it would look like: how would you design a test to tell whether someone saw red as green or whether they saw green as red?
Actually, most people who are color blind are only partially color blind, so they see it more like this:
and if you are partially color blind, this is what the top image looks like to us full trichromats:
Comments
On the other hand, maybe they do have a visual field and its being filled in by their imaginations. (i.e. mind's eye.)
I think this is what they expect over at Blue Brain, but in more detail.