class One
	class << self
		def set name, value = 0
			@values ||= {}
			@values[name] = value
		end
		def get name
			@values[name]
		end
	end
	def to_s
		self.class.get(:x)
	end
end

class Two < One
	set :x, 1
end

class Three < One
	set :x, 2
end

o1 = Two.new
o2 = Three.new
puts "#{o1.to_s} | #{o2.to_s}"