a x^2 + ay^2 +bx + cy +d =1

parametriche
x = xo +R*cos(t)
y = yo + R * sin(t)

t  (0..6.26)

C (xo,yo) (0,0)

C(xo,yo) (3,2)

r = 2
a = CurveCartesian(r * cos(t), r * sin(t), t, 0, 6.28)
b = CurveCartesian(3 + r * cos(t), 2 + r * sin(t), t, 0, 6.28)
C = (3, 2)