There are 3 large O pieces on the top and the left O piece got two O pieces hanging out from it and both of those two O pieces got 4 O pieces each on their bottom side. I also believe you can see the corner of a 4th large O piece on the back of the hotel. You can also see 16 I pieces on the side. And the windows are crap lot of T pieces. Didnt care to count them.
I believe I now hold the world record at spotting most random tetris objects on one building.