Two doors from one corner, on the left hand going east the line was broken by the entry of a court; and just at that point a certain sinister block of building thrust forward its gable on the street. It was two storeys high; showed no window, nothing but a door on the lower storey and a blind forehead of discoloured wall on the upper; and bore in every feature, the marks of prolonged and sordid negligence. –The Strange Case of Dr. Jekyll and Mr. Hyde,
Robert Louis Stevenson

Which detail from the passage establishes the gothic setting?