Cartesian curve | ovals of Descartes

(-(m^2 - n^2) (a^2 + x^2 + y^2) + 2 a x (m^2 + n^2) + k^2)^2 - 4 k^2 n^2 ((a + x)^2 + y^2) = 0

algebraic | closed | oval | polar | quartic

(data not available)

d = 4