When I read the article/essay/short story, History of Magic in North America by J.K. Rowling at Pottermore, I immediately thought of the films version of the robes in Harry Potter films 3-6/7 but red and blue. The vision is that everyone is wearing the robe with blue on the outside and red in the inside. Afterwards, I went against the idea and made a fuss about it when others did there own and...I was like “I’ll make one to.” It’s based on the colonial jackets. It’s a trade coat/frock coat. In fact, I think that is what the students were wearing in Fantastic Beasts and Where to Find Them. Of course they would be longer then those pics, and what is worn underneath would change over time to blend into the No-Maj society.