Pythagorean Quadruple Parametric Equation in 3 variables I am looking for a pythagorean quadruple generator in 3 variables. I know this one with 4 variables. $$a=2mp+2nq \\\ b=2np-2mq \\\ c=p^2+q^2-(n^2+m^2) \\\ d=p^2+q^2+n^2+m^2 $$ Anyway to do this?

a=2mp b=2np c=p^2-(m^2+n^2) d=p^2+m^2+n^2

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