Most areas on the west side (West Hollywood, Culver City, Beverly Hills) and to the north (Silver Lake, Los Feliz) have very walkable areas are all relatively safe. Downtown LA still has a sketchy history but in reality is very safe these days. It's one of the places in the city where there are legitimate lofts.
A concave polygon is defined as a polygon with one or more interior angles greater than 180Â°. It looks sort of like a vertex has been 'pushed in' towards the inside of the polygon. Note that a triangle (3-gon) can never be concave. A concave polygon is the opposite of a convex polygon. See Convex Polygon. In the figure above, drag any of the vertices around with the mouse. Take note of what it takes to make the polygon either convex or concave. Also change the number of sides.
polygon. n. 1. (Mathematics) a closed plane figure bounded by three or more straight sides that meet in pairs in the same number of vertices, and do not intersect other than at these vertices. The sum of the interior angles is (n -2) Ã 180Â° for n sides; the sum of the exterior angles is 360Â°. A regular polygon has all its sides and angles equal. Specific polygons are named according to the number of sides, such as triangle, pentagon, etc. [C16: via Latin from Greek polugÅnon figure with many angles].