sharp-pointed+projection
131Differential geometry of surfaces — Carl Friedrich Gauss in 1828 In mathematics, the differential geometry of surfaces deals with smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives:… …
132motion picture, history of the — Introduction history of the medium from the 19th century to the present. Early years, 1830–1910 Origins The illusion of motion pictures is based on the optical phenomena known as persistence of vision and the phi phenomenon. The first …
