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Cold and collected, he sees symetries, invariances and groups where we only see nice colours.
"So, the colour-charge of the three valence quarks in a hadron is a SU(3) group while the three lightest quarks, up down and strange, also share a SU(3) symmetry. This is obvious. Any questions?"
"Which is the strange quark?"
"Ahh...", said the professor in despair," the heavier of the three lightest. The first second-generation quark."
"Huh?"
"The green one..."
"Oh! Ok..."