eq1 = Eq((cos(x) - sin(y) / 2)**2 + 3 * (-sin(x) + cos(y) / 2)**2, 2)
eq2 = Eq((cos(x) - 2 * sin(y))**2 - (sin(x) + 2 * cos(y))**2, 3)
plot_contour(eq1.rewrite(Add), eq2.rewrite(Add), {"levels": [0]},
     (x, 0, 2 * pi), (y, 0, 2 * pi), is_filled=False)