Cat Eye Tests?

I heard on Cats101 that they can see 4 colors..red, blue, green and yellow.
How do they tell the 'colors' Kitty eye charts like hoomins have only with
colored mice?
I'm thinking something like laser pointers of sifferent colors. I have a
red dot one that they are addicted to and love to chase..gives them their
'running exercise' and just makes them happy and playful.
I also have a green patterned laser pointer that they love to chase too.
Yes, I play safe and make sure no eye contact with the laser happens.
Kitties are SO funny.
Sqweex just came by with a fuzzy toy in her mouth and with her mouth full,
asked me tp play.. gotta go now
Toodles
Kyla