Ruby - Class inheritance - Why is output "PUBGM"?

Question

class Game
@@play = "Fortnite"
def self.play
@@play
end
end

class Mobile_Game < Game
@@play = "PUBGM"
end

puts Game.play

Answer 1

Well, but why the subclass one "wins" over the class one?

Answer 2

class variable is shared between class and its subclass

Answer 3

by testing it, it seems so.
i'm not playing much with ruby