let's nit pick.
First, I would like to say that I wish I had a dollar for every laugh I got from this great team; now...If the professor's wife knew he hated the piano (She said it at the end)why would she buy one for his birthday?
Stan and Ollie are carrying the piano from upstairs in side the house, it seems that they are midway down the stairs when they, and the piano, fall out a window into the fountain, the same window from earlier upstairs and the same fountain,Ollies bathing suit top can be seen through his wet shirt, sort of like a wet tee shirt contest.
Before sending any hate mail...refer to my first sentence.
Never depend on anything and you will never be disappointed.