Spherical geometry other geometric concepts are defined as in plane geometry, but with straight lines replaced by great circles. Thus, in spherical geometry, angles are defined between great circles, resulting in a spherical trigonometry that differs from ordinary trigonometry in many respects; for example, the sum of the interior angles of a triangle exceeds 180 degrees. Spherical geometry is "not" elliptic geometry, but is rather a "subset" of elliptic geometry. For example, it shares with that geometry the property that a line has no parallels through a given point. Contrast this with Euclidean geometry, in which a line has one parallel through
How Many Billboards? Art Instead How Many Billboards? Art Instead How Many Billboards? Art Instead, was a large scale urban art exhibition in Los Angeles, California. The exhibition, which opened in February 2010, concurrently displayed 21 unique billboards created by various leading contemporary Californian artists. Organized by MAK Center director Kimberli Meyer and co-curated by Nizan Shaked and Dr. Gloria Sutton, the exhibition asked artists "to create a new work that critically responded to the medium of the billboard and interpreted its role in the urban landscape". Notable contemporary artist Martha Rosler and her son Josh Neufeld were among some of the commissioned artists. https://www.fastcompany.com/1559860/los-angeles-swaps-21-billboards-art