Ruby class instance variables

class A
  @value = "a"

  def self.print
    puts @value
  end
end

class B < A
  @value = "b"
end

class C < A
  @value = "c"

  def self.print
    puts @value + " -- printed by C"
  end
end

C.print # "c -- printed by C"
B.print # "b"
A.print # "a"