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.
A polygon with vertices (and sides) is known as an-gon. A polygon for which the only points of the plane belonging to two polygon edges of are the polygon vertices is said to be a simple polygon. If all sides and angles are equivalent, the polygon is called regular. Polygons can be convex, concave, or star. The word polygon derives from the Greek poly, meaning many, and gonia, meaning angle.. The most familiar type of polygon is the regular polygon, which is a convex polygon with equal sides lengths and angles.