In this episode, upon finding Mary upset in her back garden, neighbor Brenda invites her over to have a drink in the chicken coop. However, in S1E17, George Sr. had a drink in the coop with Brenda's husband, Herschel, who claimed his wife wouldn't find about his sanctuary in the coop because she's terrified of chickens.
While George is using a football-style diagram to explain to Sheldon how to get his Mom to let him go to college, the diagram looks slightly different between shots. For example: in some shots, the little chalk line into the arrowhead at the top is perfectly centered, while in others, it is slightly to the right.