Octadecagon and 2{9/4} or two enneagrams, {18/6} is reduced to 6{3} or 6 equilateral triangles, and finally {18/9} is reduced to 9{2} as nine digons. Deeper truncations of the regular enneagon and enneagrams can produce isogonal (vertex-transitive) intermediate octadecagram forms with equally spaced vertices and two edge lengths. Other truncations form double coverings: t{9/8}={18/8}=2{9/4}, t{9/4}={18/4}=2{9/2}, t{9/2}={18/2}=2{9}. The regular octadecagon is the Petrie polygon for a number of higher-dimensional polytopes, shown in these skew orthogonal projections from Coxeter planes: Octadecagon An octadecagon (or octakaidecagon) or 18-gon is an eighteen-sided polygon. A "regular octadecagon" has a Schläfli symbol {18} and can be constructed
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