
This is an interesting sketch which combines both portraiture as well as architecture. I didn't pay a lot of attention to the architecture since the cross-hatching technique was more pronounced in the facial features than in the walls.
The drawing in the book is much darker that this rendition. I used one 6B graphite pencil for the whole drawing. I am sure the original was done with a few 9B pencils, without which it is hard to get such dark shades.