Where is the 3rd difference in Tower 9 Professor Layton and Pandora's Box?

The differences in photo 8 are, 1: On the roof of Granny Riddleton's Shack tap on a a piece of the chimney near the roof. 2: Tap on the iron loop sticking up in the Centre of the circle on the ground in front of the shack. 3: Tap on the street light at the top of the stairs.

Please see the related link below for a walkthrough of the puzzle.