A Series of Unfortunate Events the plot of "The Grim Grotto", the eleventh book. The Baudelaire orphans are named after Charles Baudelaire; Violet's name also comes from the T.S. Eliot's poem "The Waste Land", specifically its verses concerning the "violet hour," and Sunny and Klaus take their first names from Claus and Sunny von Bülow, while Mr. Poe is a reference to Edgar Allan Poe (his sons are named Edgar and Albert). In the seventh installment, "The Vile Village," Count Olaf's disguise, Detective Dupin, is an allusion to C. Auguste Dupin, a fictional detective created by Edgar Allan Poe. Isadora and Duncan Quagmire are named
Dupin indicatrix Dupin indicatrix In differential geometry, the Dupin indicatrix is a method for characterising the local shape of a surface. Draw a plane parallel to the tangent plane and a small distance away from it. Consider the intersection of the surface with this plane. The shape of the intersection is related to the Gaussian curvature. The Dupin indicatrix is the result of the limiting process as the plane approaches the tangent plane. The indicatrix was invented by Charles Dupin. For elliptical points where the Gaussian curvature is positive the intersection will either be empty or form a closed curve. In the