"Isoline" (1888), and "Le mari de la reine" (1889). An isosurface is a three-dimensional analog of an isoline. According to the END five dBA ranges are used for this contour (isoline) representation. Titania, the godmother of Isoline promises to protect the princess against the plans of Oberon. When Isolin returns, Isoline, thinking he wants to marry her through pity, repulses him.