San Francisco (sans-serif typeface) and iOS 10 is a new variant named "SF Compact Rounded". It is used in the new contact placeholder icons introduced in the OSes. The "SF Serif" variant was showcased during the keynote at WWDC 2018 on June 4, 2018 when the all-new Apple Books app was introduced. This variant is exclusive to Apple Books in iOS 12 and macOS Mojave, is not mentioned in Apple's Typography design guidelines, and is not publicly downloadable like other variants of the San Francisco typeface. Since its introduction, San Francisco has gradually replaced most of Apple's other typefaces on their software and hardware
Sans-serif create rational, almost neutral typefaces. In 1957 the release of Helvetica, Univers, and Folio, the first typefaces categorized as neo-grotesque, had a strong impact internationally: Helvetica came to be the most used typeface for the following decades. Other, later neo-grotesques include Unica, Imago and Rail Alphabet, and in the digital period Acumin, San Francisco and Roboto. As their name suggests, Geometric sans-serif typefaces are based on geometric shapes, like near-perfect circles and squares. Common features are a nearly-exactly circular capital "O" and a "single-story" lowercase letter "a". The 'M' is often splayed and the capitals of varying width, following the