A foil is a character that is opposite of the main character and makes the main character's personality seem stronger and more enhanced
Bodoni is the main character/protagonist because he is perseverant and creative. He is perseverant because even when Bramante telling him to give up on his dreams he doesn't and thinks up better ways to succeed. He is also Creative because he thought up the "rocket" idea, not everyone would be able to think that up but he does.
Bramante is Bodoni's foil because he feels surrendered and useless. Bramante feels surrendered because he does not try to do anything succesful and comes to the conclusion that he will never become rich. He also feels useless because he never tries anything and doesn't really care about anything anymore.