The study of spheres dates back to the first century in the book Sphaerica of Menelaus. Spherical trigonometry was thoroughly developed in modern form by Euler in his 1782 paper [?]. Spherical geometry in n-dimensions was first studied by Schläfli in his 1852 treatise, which was published posthumously in 1901 [?]. The most important transformation in spherical geometry, Möbius transformation, w...
