Off topic but there has recently been some studies of people with inactive cones seeing a simplified colour set with rods! The reason rods have been asociated with black & white is because they turn on at much lower intensities than cones; but they don't become colour active until intensities that would turn on cones anyway. Once the cones turn on they drown out the colour info from the rods. Therefore it has now been assumed that dogs see in colour too!

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"You can't talk to a brick wall but you can do Graffiti"