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 to Have Sex in an Epidemic MSM in New York City and San Francisco had been infected. Retrospective analysis by the CDC found that there were between 250,000-300,000 people living with HIV in the United States in 1983, and the number of people newly infected between `83-`84 was around 150,000). However, the model set forth by Callen and Berkowitz at least provided the possibility of a "return to intimacy" for people with AIDS, which, despite being based on a now-defunct notion of how the syndrome arose, was important in combating the social death that many PWA faced after diagnosis. "How to Have Sex in an Epidemic"