I agree with Pluckman! Great perspective demonstrated in the vertical lines. (there should be a better word for lines going across the Z axis)
The horizontal lines are off though. The distance between them should logarithmically decrease as they go back; right now the squares look like they're getting longer the further back they go. Also the sun is off center, but there's not much you can do about it except for cut off a bunch of your work, I suppose...
Still, I really like it. I'm excited to see how it ends up looking in the end.