- The Broadview neighborhood bordering Puget Sound in northwest Seattle takes its name from the expansive views of Puget Sound and the Olympic Mountains that can be seen from its western slopes. The neighborhood reaches north from N 105th Street to the city limits at N 145th Street, and is bounded on the east by Aurora Avenue N. It is home to Carkeek Park, Evergreen Park Cemetery, the Ida Culver Retirement Home, and Bitter Lake, which beckoned many of the first settlers to the area. It drew its identity from an amusement park called Playland that operated on the south shore of Bitter Lake for 30 years, beginning in 1930. The Seattle-Everett Interurban trolley line ran through the heart of the neighborhood, bringing people and goods to the area and hastening its development. Broadview, once forestland and rural farmland, today is a suburban home to 13,000 residents.
- Klein bottle (Wikipedia)
In mathematics, the Klein bottle (/ˈklaɪn/) is an example of a non-orientable surface; that is, informally, a one-sided surface which, if traveled upon, could be followed back to the point of origin while flipping the traveler upside down. More formally, the Klein bottle is a two-dimensional manifold on which one cannot define a normal vector at each point that varies continuously over the whole manifold. Other related non-orientable surfaces include the Möbius strip and the real projective plane. While a Möbius strip is a surface with a boundary, a Klein bottle has no boundary. For comparison, a sphere is an orientable surface with no boundary.