Crime fiction by the Danish author Steen Steensen Blicher, published in 1829. Better known are the earlier dark works of Edgar Allan Poe. His brilliant and eccentric detective C. Auguste Dupin, a forerunner to Arthur Conan Doyle’s Sherlock Holmes, appeared in works such as "The Murders in the Rue Morgue" (1841), "The Mystery of Marie Roget" (1842), and "The Purloined Letter" (1844). With his Dupin stories, Poe provided the framework for the classic detective story. The detective’s unnamed companion is the narrator of the stories and a prototype for the character of Dr. Watson in later Sherlock Holmes stories. Wilkie Collins' epistolary
Dupin cyclide also used to refer to a more general class of quartic surfaces which are important in the theory of separation of variables for the Laplace equation in three dimensions. Dupin cyclides were investigated not only by Dupin, but also by A. Cayley und J.C. Maxwell. Today, Dupin cylides are used in computer-aided design (CAD), because cyclide patches have rational representations and are suitable for blending canal surfaces (cylinder, cones, tori, and others). There are several equivalent definitions of Dupin cyclides. In formula_1, they can be defined as the images under any inversion of tori, cylinders and double cones. This shows