flattening in the inner regions of our galaxies. In some galaxies, such as ESO142-G24 or ESO157-G18, the warp sets off in one direction, turns back to the mean plane, and ends in the opposite hemisphere. The Milky Way’s warp in the Southern Hemisphere is an example of this type of behaviour (Porcel et al. 1997). Florido et al. (1991) also report such ‘elbow’-type warps. This effect may come from the presence of a more strongly warped dust lane (than the stellar disc) or be an intrinsic effect associated with warps. For such galaxies, a four-parameter fit would have provided a better description. However, since an excessive number of fit parameters renders any interpretation of simple warps unclear, we prefer to use three-parameter fits.

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  Galaxy                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              

                                                                                                                                                  $\omega$                                                                                                                                     $\omega_{\rm R}$   $\omega_{\rm L}$   $\alpha_{\rm s}$    $\omega$    $\omega_{\rm R}$   $\omega_{\rm L}$   $\alpha_{\rm s}$    $\omega$    $\omega_{\rm R}$   $\omega_{\rm L}$   $\alpha_{\rm s}$    $\omega$    $\omega_{\rm R}$   $\omega_{\rm L}$   $\alpha_{\rm s}$

  ESO026-G06                                                                                                                                      1$\pm$3                                                                                                                                          1$\pm$3           $-$0$\pm$3                          0$\pm$2         1$\pm$2           $-$1$\pm$2                          2$\pm$3         2$\pm$3            1$\pm$3                           $-$3$\pm$3      $-$2$\pm$3         $-$1$\pm$3     

  ESO033-G22                                                                                                                                     $-$1$\pm$4                                                                                                                                        0$\pm$4           $-$1$\pm$4                         $-$3$\pm$6      $-$1$\pm$6         $-$2$\pm$6                         $-$1$\pm$4      $-$1$\pm$4          0$\pm$4                            3$\pm$4         1$\pm$4            1$\pm$4       

  ESO142-G24                                                **[3$\pm$2]{} & **[4$\pm$2]{} & 