I'm trying to make a 3D contour plot the polynomial equation
$$(x^2 + y^2 + z^2 - 4)^2 == 0, \quad \quad (1)$$
Without power 2
$$ (x^2 + y^2 + z^2 - 4) == 0, \quad \quad (2)$$
it plots a sphere with radius 2. With power 2 $(1)$ it plots an empty set.
My motivation is to 3D contour plot the polynomial equation
$$ (x^2 + y^2 + z^2 - 4)^2 + ((x - 1)^2 + y^2 - 1)^2 == 0, \quad \quad (3) $$
But the result is the same as in $(1)$. (Plotting this solution set might be even more tricky as it is not a surface, but a 3D curve;)
These polynomials don't seem to be very complex (max. deg. 4) and with some modification (as with adding +x) it plots.
I'm looking forward to any idea to fix that and so I can produce a 3D contour plot these polynomials.