You can find walkable, safe neighborhoods all across the city, so it will likely come down to the location of your work, and the type of lifestyle you prefer (laid back, in the scene, family life, etc.). I live on the west side myself, so I'll speak to this area.
What is a Concave Wheel? Concave Technology takes the center of the wheel and dips inwards to give it that bowl effect. Rather than exaggerating a bigger lip for the back wheel, and a smaller lip for the front. Concave wheels emphasize the concavity of the rear wheel to differentiate from the front wheel.
Concave polygons can be seen in the floor plan of a house or patio. Here, the bay window creates a concave polygon shape for one room of the house. You can see that the orange diagonal passes outside of the shape. A cross is an excellent example of a concave polygon.