\({\left( {x - \dfrac{{36}}{{49}}} \right)^2} + {\left( {y - \dfrac{{18}}{{49}}} \right)^2} + {\left( {z - \dfrac{{12}}{{49}}} \right)^2} = \dfrac{{25}}{{49}}\)   

\({\left( {x - \dfrac{1}{2}} \right)^2} + {\left( {y - \dfrac{1}{4}} \right)^2} + {\left( {z - \dfrac{1}{6}} \right)^2} = \dfrac{{49}}{{144}}\)

\({x^2} + {\left( {y + 1} \right)^2} + {\left( {z - 2} \right)^2} = 4\)            

\({x^2} + {\left( {y - 1} \right)^2} + {\left( {z - 2} \right)^2} = 4\)