>>13915602x^2 = r = parallel lines
x^2 + y^2 = r = circle
x^2+ y^2 = r^2 = circle in positive & negative planes
X^2+y^2+z^2 = r / x^2+y^2+z^2 = sphere of some sort
x^2+i^2+z^2 = infinite paraboloid
x^2+y^2+z^2 = r = circle
x^2+y^2+z^2+i^2 = sphere/quaternion
