class variables in metaclass.rb

class Object
  def metaclass
    class << self; self; end
  end
end

class Tea
  @@liters = 5
  class << Tea
    def spill_all
      @@liters = 0
    end
  end
end

p Tea.send(:class_variable_get, :@@liters) # => 5
Tea.spill_all
p Tea.send(:class_variable_get, :@@liters) # => 0

class Coffee
  @@liters = 5
end
class << Coffee
  def spill_all
    @@liters = 0
  end
end

p Coffee.send(:class_variable_get, :@@liters) # => 5
Coffee.spill_all
p Coffee.send(:class_variable_get, :@@liters) # => 5 (?)
p Coffee.metaclass.send(:class_variable_get, :@@liters) # => 0 (!)