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 Many Clouds Can You See? How Many Clouds Can You See? How Many Clouds Can You See? is the second album by English saxophonist John Surman featuring Harry Beckett, Alan Skidmore, Barre Phillips and Tony Oxley recorded in 1970 and released on the Deram label. Allmusic awards the album 4 and a half stars and its review by Jason Ankeny states: "John Surman's second album remains his most impressive, anticipating the sound and scope of the European free jazz movement that would blossom in the decade to come". John Kelman in his All About Jazz review states: "While woodwind multi-instrumentalist John Surman's eponymous debut was