Continuity goofs: This episode and the previous one were reversed. Because, as you can see, the girls room is still pink. They didn't get the yellow wallpaper until the previous episode.
Note: This episode was filmed two full episodes before this one. It was just shown out of order. The production code numbers in the upper right corners of these guides will show what order the shows were actually done it. The episode number will show you the order on TV.