Octadecagon 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 as a quasiregular truncated enneagon, t{9}, which alternates two types of edges. As 18 = 2 × 3, a regular octadecagon cannot be constructed using a compass and straightedge. However, it is constructible using neusis, or an angle trisection with a tomahawk. The following approximate construction is very similar to that of the enneagon, as an octadecagon can be constructed as a truncated enneagon. It is also feasible with exclusive use of compass and straightedge. The "regular
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"