Go to the part where the teacher and Tony are arguing about Billy tap dancing. They get in this long argument, and then it shows Billy in an alleyway like place with the bathrooms. He starts dancing all over the place, then he's dancing down the street doing tap dancing moves, and you can hear tap shoes like they're on his feet. However, #1, he doesn't have tap shoes on; he has boots. #2, tap shoes don't work on cement.