A shell (Jeener surface 1) [Un coquillage (surface de Jeener 1)].

                               ku
                    F (u,v) = e  (1+cos(v))cos(u)
                     x


                               ku
                    F (u,v) = e  (1+cos(v))sin(u)
                     y


                               ku
                    F (u,v) = e  (2+sin(v))
                     z

                         log(2)
                    k = --------
                          2.pi


                    u ∈ [-2.pi,+2.pi]


                            pi
                    v ∈ [- ----,+pi]
                            2

                    RADIUS = constant


                                     dF (u,v)       dF (u,v)
                                       x              x
                    RED    = 1 - K (----------Du + ----------Dv)
                                  R     du             dv


                                     dF (u,v)       dF (u,v)
                                       y              y
                    GREEN  = 1 - K (----------Du + ----------Dv)
                                  V     du             dv


                                     dF (u,v)       dF (u,v)
                                       z              z
                    BLUE   = 1 - K (----------Du + ----------Dv)
                                  B     du             dv

                          8.pi
                    Du = ------
                           200


                          3.pi
                    Dv = ------
                           200

See an artistic variation on a geometrical inversion of this shell.

See a special shell.