From what I've heard about Jane Street interviews from people who interviewed there for intern and new grad positions, they involve solving mathematical puzzles

From what I've heard about Jane Street interviews from people who interviewed there for intern and new grad positions, they involve solving mathematical puzzles about probability, statistics, and betting. I know multiple people who were invited to onsite interviews, including in one case for a trading position, who were in progress on math and computer science degrees, and had no specific finance knowledge. I also know people who have done trading internships at other firms with no finance experience. It seems entirely reasonable to me that Jane Street would consider a Bachelor's degree from MIT in math or computer science, being clever, and a prior internship at Jane Street as qualification to work at Jane Street.