There seems to be many versions of colourblind. I think I am red-green colourblind. People say to me, "What colour is the sky?" "What about grass?" Yet, I think the term itself is a misnomer (probably because I am defective!). Just because the majority has a certain trait, why is the minority therefore "blind"? I think there is an evolutionary for this abnormality. If I remember correctly, there are night vision advantages, or something like that. Therefore, to be different can give you an advantage. I mean look at giraffes and their massive necks! (Don't ask me what colour they are!)