Close-captioning during the opening sequence credits Mailbox as saying "I can play!" when the correct line is actually "Right this way!" This mistake is only found on the DVD version of the episode.
Mailtime Segment: Mailbox points out that our letter is a rectangular shape and it has a square-shaped stamp. In the letter, two kids, with an accompanying parent, search for shapes in their neighborhood. Specifically, they're looking for circles and they find them on signs, on a parking meter, on traffic lights and many other places.