| Implicit curves and surfaces Zero-sum curves and surfaces Implicitly defined curves  (left graphic) and  (right graphic) in the  ,  ‐plane. Implicitly defined surface  (left graphic) and  (right graphic) in  ,  ,  ‐space. Implicitly defined surface  in  ,  ,  ‐space. Implicitly defined surfaces  (empty left graphic) and  (empty right graphic) in  ,  ,  ‐space. |