Being a native who's studied colonialism means that I know wayyyyy too much about blood quantum. I know how stupid it is, how it's tied to eugenics, but I also know how it "works."
Which means I can use my stupid-power to do this:
Well this took a turn.
Alyssa VELARYON gave birth to Jaehaerys and Alysanne Targaryen - making them 50% targaryen 50% velaryon They married each other, making all their kids 50% velaryon Baelon and Alyssa, their kids, married and had Viserys and Daemon, both 50% velaryon 50% Targ Daella married Rodrik Arryn, had Aemma 50% Arryn 25% Targ 25% Velaryon (We don't know Rodrik's mother so he's down as 100% Arryn but in reality he's a mix of his maternal heritage too)
Aemma and Viserys married producing Rhaenyra 37.5% Targ 37.5% Velaryon 25% Arryn Her kids have fucking Velaryon blood regardless of the parentage which is AMBIGUOUS in Fire and Blood and the boys were legally claimed as Laenor's by Laenor and Corlys
so suck it Vaemond you useless sexist