Arthur Conan Doyle study of such a character [viz., Bell] I used and amplified his methods when in later life I tried to build up a scientific detective who solved cases on his own merits and not through the folly of the criminal." Robert Louis Stevenson was able, even in faraway Samoa, to recognise the strong similarity between Joseph Bell and Sherlock Holmes: "My compliments on your very ingenious and very interesting adventures of Sherlock Holmes. ... can this be my old friend Joe Bell?" Other authors sometimes suggest additional influences—for instance, the famous Edgar Allan Poe character C. Auguste Dupin. Dr. (John)
Dupin cyclide that the class of Dupin cyclides is invariant under Möbius (or conformal) transformations. In complex space formula_2 these three latter varieties can be mapped to one another by inversion, so Dupin cyclides can be defined as inversions of the torus (or the cylinder, or the double cone). Since a standard torus is the orbit of a point under a two dimensional abelian subgroup of the Möbius group, it follows that the cyclides also are, and this provides a second way to define them. A third property which characterizes Dupin cyclides is that their curvature lines are all circles (possibly through