Here, everything's perfect.
Vision first : A wonderful use of the environment. Focus and exposure on the wall, to get the man in the frame, ou of focus, a simple outline. Excellent.
And so really original.
The composition. The focused part take one third of the left of the picture. Really well balanced. The wall itself take an half of the frame, and composes a picture based on opposition :
The wall, plain and sharp, against the empty space of a private alley.
The soft tones of the stone, against the hard outline of the man where white and black fight.
The reality of a wall, and the appearance of a shadow fading on the distance.
Everything in a square, which is the perfect format for the composition.
I wish I could have a better english to describe it.