As I was walking through Glasgow I noticed they were demolishing a building which left marks behind on the next building creating an interesting puzzle.
Its obvious from the black marks on the wall that another building was added later blocking several windows. One puzzle is why the black does not go all the way to the ground. At some point before the building that left the black mark was built there was a small one on the left where the stone looks like it has never gotten dirty and where there was a door. Another puzzle is why is some of the wall a lot cleaner than other bits? it would have all been pretty black in the past (thats what using coal to provide all your energy does) but it now is not except in patches. Is this just a bad cleaning Job?
I do have one clue about the building that was knocked down because its in one of my old photos.
The small building behind the partially demolished one is the missing building. I have no idea what it was. It would have been built in the back court of the buildings surrounding it taking up the spare space and blocking the light on the lower floors.