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.
Truncated Tetrahedron: Polygon A polygon is a two dimensional figure made up of line segments called edges, that are connected two at a time at their endpoints. In a polyhedron, several polygonal faces meet at a corner (vertex). When all the edges of the polygon are of equal length the polygon is called regular. Polygons whose sides and angles are not of equal measure, are said to be irregular. A polygon is a closed plane figure bounded by straight line segments.